diff --git a/docs/en_US/NAS/retiarii/ApiReference.rst b/docs/en_US/NAS/retiarii/ApiReference.rst
index 67315e195a..1e49b8fcef 100644
--- a/docs/en_US/NAS/retiarii/ApiReference.rst
+++ b/docs/en_US/NAS/retiarii/ApiReference.rst
@@ -72,10 +72,16 @@ Oneshot Trainers
 Strategies
 ----------
 
-..  autoclass:: nni.retiarii.strategies.RandomStrategy
+..  autoclass:: nni.retiarii.strategy.Random
     :members:
 
-..  autoclass:: nni.retiarii.strategies.TPEStrategy
+..  autoclass:: nni.retiarii.strategy.GridSearch
+    :members:
+
+..  autoclass:: nni.retiarii.strategy.RegularizedEvolution
+    :members:
+
+..  autoclass:: nni.retiarii.strategy.TPEStrategy
     :members:
 
 Retiarii Experiments
diff --git a/docs/en_US/NAS/retiarii/Tutorial.rst b/docs/en_US/NAS/retiarii/Tutorial.rst
index 925827adeb..9a9305cf96 100644
--- a/docs/en_US/NAS/retiarii/Tutorial.rst
+++ b/docs/en_US/NAS/retiarii/Tutorial.rst
@@ -167,13 +167,13 @@ In the following table, we listed the available trainers and strategies.
     - TPEStrategy
     - DartsTrainer
   * - Regression
-    - RandomStrategy
+    - Random
     - EnasTrainer
   * - 
-    - 
+    - GridSearch
     - ProxylessTrainer
   * - 
-    - 
+    - RegularizedEvolution
     - SinglePathTrainer (RandomTrainer)
 
 There usage and API document can be found `here <./ApiReference>`__\.
@@ -204,7 +204,7 @@ After all the above are prepared, it is time to start an experiment to do the mo
 
 .. code-block:: python
 
-  exp = RetiariiExperiment(base_model, trainer, applied_mutators, simple_startegy)
+  exp = RetiariiExperiment(base_model, trainer, applied_mutators, simple_strategy)
   exp_config = RetiariiExeConfig('local')
   exp_config.experiment_name = 'mnasnet_search'
   exp_config.trial_concurrency = 2
diff --git a/docs/en_US/NAS/retiarii/WriteStrategy.rst b/docs/en_US/NAS/retiarii/WriteStrategy.rst
index d8f10546f8..6f354b3b85 100644
--- a/docs/en_US/NAS/retiarii/WriteStrategy.rst
+++ b/docs/en_US/NAS/retiarii/WriteStrategy.rst
@@ -3,10 +3,12 @@ Customize A New Strategy
 
 To write a new strategy, you should inherit the base strategy class ``BaseStrategy``, then implement the member function ``run``. This member function takes ``base_model`` and ``applied_mutators`` as its input arguments. It can simply apply the user specified mutators in ``applied_mutators`` onto ``base_model`` to generate a new model. When a mutator is applied, it should be bound with a sampler (e.g., ``RandomSampler``). Every sampler implements the ``choice`` function which chooses value(s) from candidate values. The ``choice`` functions invoked in mutators are executed with the sampler.
 
-Below is a very simple random strategy, the complete code can be found :githublink:`here <nni/retiarii/strategies/random_strategy.py>`.
+Below is a very simple random strategy, which makes the choices completely random.
 
 .. code-block:: python
 
+    from nni.retiarii import Sampler
+
     class RandomSampler(Sampler):
         def choice(self, candidates, mutator, model, index):
             return random.choice(candidates)
@@ -31,6 +33,6 @@ Below is a very simple random strategy, the complete code can be found :githubli
                 else:
                     time.sleep(2)
 
-You can find that this strategy does not know the search space beforehand, it passively makes decisions every time ``choice`` is invoked from mutators. If a strategy wants to know the whole search space before making any decision (e.g., TPE, SMAC), it can use ``dry_run`` function provided by ``Mutator`` to obtain the space. An example strategy can be found :githublink:`here <nni/retiarii/strategies/tpe_strategy.py>`.
+You can find that this strategy does not know the search space beforehand, it passively makes decisions every time ``choice`` is invoked from mutators. If a strategy wants to know the whole search space before making any decision (e.g., TPE, SMAC), it can use ``dry_run`` function provided by ``Mutator`` to obtain the space. An example strategy can be found :githublink:`here <nni/retiarii/strategy/tpe_strategy.py>`.
 
 After generating a new model, the strategy can use our provided APIs (e.g., ``submit_models``, ``is_stopped_exec``) to submit the model and get its reported results. More APIs can be found in `API References <./ApiReference.rst>`__.
\ No newline at end of file
diff --git a/nni/retiarii/execution/base.py b/nni/retiarii/execution/base.py
index 1ce1d00da3..52baf3075d 100644
--- a/nni/retiarii/execution/base.py
+++ b/nni/retiarii/execution/base.py
@@ -65,11 +65,11 @@ def _send_trial_callback(self, paramater: dict) -> None:
         if self.resources <= 0:
             _logger.warning('There is no available resource, but trial is submitted.')
         self.resources -= 1
-        _logger.info('on_resource_used: %d', self.resources)
+        _logger.info('Resource used. Remaining: %d', self.resources)
 
     def _request_trial_jobs_callback(self, num_trials: int) -> None:
         self.resources += num_trials
-        _logger.info('on_resource_available: %d', self.resources)
+        _logger.info('New resource available. Remaining: %d', self.resources)
 
     def _trial_end_callback(self, trial_id: int, success: bool) -> None:
         model = self._running_models[trial_id]
diff --git a/nni/retiarii/experiment/pytorch.py b/nni/retiarii/experiment/pytorch.py
index ee08ea994b..1b8c598a91 100644
--- a/nni/retiarii/experiment/pytorch.py
+++ b/nni/retiarii/experiment/pytorch.py
@@ -17,7 +17,7 @@
 from ..integration import RetiariiAdvisor
 from ..mutator import Mutator
 from ..nn.pytorch.mutator import process_inline_mutation
-from ..strategies.strategy import BaseStrategy
+from ..strategy import BaseStrategy
 from ..trainer.interface import BaseOneShotTrainer, BaseTrainer
 from ..utils import get_records
 
diff --git a/nni/retiarii/graph.py b/nni/retiarii/graph.py
index f8a99b7eb9..fa1b136ff4 100644
--- a/nni/retiarii/graph.py
+++ b/nni/retiarii/graph.py
@@ -131,7 +131,7 @@ def fork(self) -> 'Model':
         new_model = Model(_internal=True)
         new_model._root_graph_name = self._root_graph_name
         new_model.graphs = {name: graph._fork_to(new_model) for name, graph in self.graphs.items()}
-        new_model.training_config = copy.deepcopy(self.training_config)
+        new_model.training_config = copy.deepcopy(self.training_config)  # TODO this may be a problem when training config is large
         new_model.history = self.history + [self]
         return new_model
 
diff --git a/nni/retiarii/strategies/__init__.py b/nni/retiarii/strategies/__init__.py
deleted file mode 100644
index 62ef50bf4f..0000000000
--- a/nni/retiarii/strategies/__init__.py
+++ /dev/null
@@ -1,2 +0,0 @@
-from .tpe_strategy import TPEStrategy
-from .random_strategy import RandomStrategy
diff --git a/nni/retiarii/strategies/random_strategy.py b/nni/retiarii/strategies/random_strategy.py
deleted file mode 100644
index 78c1ac13da..0000000000
--- a/nni/retiarii/strategies/random_strategy.py
+++ /dev/null
@@ -1,32 +0,0 @@
-import logging
-import random
-import time
-
-from .. import Sampler, submit_models, query_available_resources
-from .strategy import BaseStrategy
-
-_logger = logging.getLogger(__name__)
-
-class RandomSampler(Sampler):
-    def choice(self, candidates, mutator, model, index):
-        return random.choice(candidates)
-
-class RandomStrategy(BaseStrategy):
-    def __init__(self):
-        self.random_sampler = RandomSampler()
-
-    def run(self, base_model, applied_mutators):
-        _logger.info('stargety start...')
-        while True:
-            avail_resource = query_available_resources()
-            if avail_resource > 0:
-                model = base_model
-                _logger.info('apply mutators...')
-                _logger.info('mutators: %s', str(applied_mutators))
-                for mutator in applied_mutators:
-                    mutator.bind_sampler(self.random_sampler)
-                    model = mutator.apply(model)
-                # run models
-                submit_models(model)
-            else:
-                time.sleep(2)
diff --git a/nni/retiarii/strategy/__init__.py b/nni/retiarii/strategy/__init__.py
new file mode 100644
index 0000000000..af8810873b
--- /dev/null
+++ b/nni/retiarii/strategy/__init__.py
@@ -0,0 +1,4 @@
+from .base import BaseStrategy
+from .bruteforce import Random, GridSearch
+from .evolution import RegularizedEvolution
+from .tpe_strategy import TPEStrategy
diff --git a/nni/retiarii/strategies/strategy.py b/nni/retiarii/strategy/base.py
similarity index 100%
rename from nni/retiarii/strategies/strategy.py
rename to nni/retiarii/strategy/base.py
diff --git a/nni/retiarii/strategy/bruteforce.py b/nni/retiarii/strategy/bruteforce.py
new file mode 100644
index 0000000000..a7d965fe91
--- /dev/null
+++ b/nni/retiarii/strategy/bruteforce.py
@@ -0,0 +1,115 @@
+import copy
+import itertools
+import logging
+import random
+import time
+from typing import Any, Dict, List
+
+from .. import Sampler, submit_models, query_available_resources
+from .base import BaseStrategy
+from .utils import dry_run_for_search_space, get_targeted_model
+
+_logger = logging.getLogger(__name__)
+
+
+def grid_generator(search_space: Dict[Any, List[Any]], shuffle=True):
+    keys = list(search_space.keys())
+    search_space_values = copy.deepcopy(list(search_space.values()))
+    if shuffle:
+        for values in search_space_values:
+            random.shuffle(values)
+    for values in itertools.product(*search_space_values):
+        yield {key: value for key, value in zip(keys, values)}
+
+
+def random_generator(search_space: Dict[Any, List[Any]], dedup=True, retries=500):
+    keys = list(search_space.keys())
+    history = set()
+    search_space_values = copy.deepcopy(list(search_space.values()))
+    while True:
+        for retry_count in range(retries):
+            selected = [random.choice(v) for v in search_space_values]
+            if not dedup:
+                break
+            selected = tuple(selected)
+            if selected not in history:
+                history.add(selected)
+                break
+            if retry_count + 1 == retries:
+                _logger.info('Random generation has run out of patience. There is nothing to search. Exiting.')
+                return
+        yield {key: value for key, value in zip(keys, selected)}
+
+
+class GridSearch(BaseStrategy):
+    """
+    Traverse the search space and try all the possible combinations one by one.
+
+    Parameters
+    ----------
+    shuffle : bool
+        Shuffle the order in a candidate list, so that they are tried in a random order. Default: true.
+    """
+
+    def __init__(self, shuffle=True):
+        self._polling_interval = 2.
+        self.shuffle = shuffle
+
+    def run(self, base_model, applied_mutators):
+        search_space = dry_run_for_search_space(base_model, applied_mutators)
+        for sample in grid_generator(search_space, shuffle=self.shuffle):
+            _logger.info('New model created. Waiting for resource. %s', str(sample))
+            if query_available_resources() <= 0:
+                time.sleep(self._polling_interval)
+            submit_models(get_targeted_model(base_model, applied_mutators, sample))
+
+
+class _RandomSampler(Sampler):
+    def choice(self, candidates, mutator, model, index):
+        return random.choice(candidates)
+
+
+class Random(BaseStrategy):
+    """
+    Random search on the search space.
+
+    Parameters
+    ----------
+    variational : bool
+        Do not dry run to get the full search space. Used when the search space has variational size or candidates. Default: false.
+    dedup : bool
+        Do not try the same configuration twice. When variational is true, deduplication is not supported. Default: true.
+    """
+
+    def __init__(self, variational=False, dedup=True):
+        self.variational = variational
+        self.dedup = dedup
+        if variational and dedup:
+            raise ValueError('Dedup is not supported in variational mode.')
+        self.random_sampler = _RandomSampler()
+        self._polling_interval = 2.
+
+    def run(self, base_model, applied_mutators):
+        if self.variational:
+            _logger.info('Random search running in variational mode.')
+            sampler = _RandomSampler()
+            for mutator in applied_mutators:
+                mutator.bind_sampler(sampler)
+            while True:
+                avail_resource = query_available_resources()
+                if avail_resource > 0:
+                    model = base_model
+                    for mutator in applied_mutators:
+                        model = mutator.apply(model)
+                    _logger.info('New model created. Applied mutators are: %s', str(applied_mutators))
+                    submit_models(model)
+                else:
+                    time.sleep(self._polling_interval)
+        else:
+            _logger.info('Random search running in fixed size mode. Dedup: %s.', 'on' if self.dedup else 'off')
+            search_space = dry_run_for_search_space(base_model, applied_mutators)
+            for sample in random_generator(search_space, dedup=self.dedup):
+                _logger.info('New model created. Waiting for resource. %s', str(sample))
+                if query_available_resources() <= 0:
+                    time.sleep(self._polling_interval)
+                submit_models(get_targeted_model(base_model, applied_mutators, sample))
diff --git a/nni/retiarii/strategy/evolution.py b/nni/retiarii/strategy/evolution.py
new file mode 100644
index 0000000000..fa365a8382
--- /dev/null
+++ b/nni/retiarii/strategy/evolution.py
@@ -0,0 +1,158 @@
+import collections
+import dataclasses
+import logging
+import random
+import time
+
+from ..execution import query_available_resources, submit_models
+from ..graph import ModelStatus
+from .base import BaseStrategy
+from .utils import dry_run_for_search_space, get_targeted_model
+
+
+_logger = logging.getLogger(__name__)
+
+
+@dataclasses.dataclass
+class Individual:
+    """
+    A class that represents an individual.
+    Holds two attributes, where ``x`` is the model and ``y`` is the metric (e.g., accuracy).
+    """
+    x: dict
+    y: float
+
+
+class RegularizedEvolution(BaseStrategy):
+    """
+    Algorithm for regularized evolution (i.e. aging evolution).
+    Follows "Algorithm 1" in Real et al. "Regularized Evolution for Image Classifier Architecture Search".
+
+    Parameters
+    ----------
+    optimize_mode : str
+        Can be one of "maximize" and "minimize". Default: maximize.
+    population_size : int
+        The number of individuals to keep in the population. Default: 100.
+    cycles : int
+        The number of cycles (trials) the algorithm should run for. Default: 20000.
+    sample_size : int
+        The number of individuals that should participate in each tournament. Default: 25.
+    mutation_prob : float
+        Probability that mutation happens in each dim. Default: 0.05
+    on_failure : str
+        Can be one of "ignore" and "worst". If "ignore", simply give up the model and find a new one.
+        If "worst", mark the model as -inf (if maximize, inf if minimize), so that the algorithm "learns" to avoid such model.
+        Default: ignore.
+    """
+
+    def __init__(self, optimize_mode='maximize', population_size=100, sample_size=25, cycles=20000,
+                 mutation_prob=0.05, on_failure='ignore'):
+        assert optimize_mode in ['maximize', 'minimize']
+        assert on_failure in ['ignore', 'worst']
+        assert sample_size < population_size
+        self.optimize_mode = optimize_mode
+        self.population_size = population_size
+        self.sample_size = sample_size
+        self.cycles = cycles
+        self.mutation_prob = mutation_prob
+        self.on_failure = on_failure
+
+        self._worst = float('-inf') if self.optimize_mode == 'maximize' else float('inf')
+
+        self._success_count = 0
+        self._population = collections.deque()
+        self._running_models = []
+        self._polling_interval = 2.
+
+    def random(self, search_space):
+        return {k: random.choice(v) for k, v in search_space.items()}
+
+    def mutate(self, parent, search_space):
+        child = {}
+        for k, v in parent.items():
+            if random.uniform(0, 1) < self.mutation_prob:
+                # NOTE: we do not exclude the original choice here for simplicity,
+                # which is slightly different from the original paper.
+                child[k] = random.choice(search_space[k])
+            else:
+                child[k] = v
+        return child
+
+    def best_parent(self):
+        samples = [p for p in self._population]  # copy population
+        random.shuffle(samples)
+        samples = list(samples)[:self.sample_size]
+        if self.optimize_mode == 'maximize':
+            parent = max(samples, key=lambda sample: sample.y)
+        else:
+            parent = min(samples, key=lambda sample: sample.y)
+        return parent.x
+
+    def run(self, base_model, applied_mutators):
+        search_space = dry_run_for_search_space(base_model, applied_mutators)
+        # Run the first population regardless concurrency
+        _logger.info('Initializing the first population.')
+        while len(self._population) + len(self._running_models) <= self.population_size:
+            # try to submit new models
+            while len(self._population) + len(self._running_models) < self.population_size:
+                config = self.random(search_space)
+                self._submit_config(config, base_model, applied_mutators)
+            # collect results
+            self._move_succeeded_models_to_population()
+            self._remove_failed_models_from_running_list()
+            time.sleep(self._polling_interval)
+
+            if len(self._population) >= self.population_size:
+                break
+
+        # Resource-aware mutation of models
+        _logger.info('Running mutations.')
+        while self._success_count + len(self._running_models) <= self.cycles:
+            # try to submit new models
+            while query_available_resources() > 0 and self._success_count + len(self._running_models) < self.cycles:
+                config = self.mutate(self.best_parent(), search_space)
+                self._submit_config(config, base_model, applied_mutators)
+            # collect results
+            self._move_succeeded_models_to_population()
+            self._remove_failed_models_from_running_list()
+            time.sleep(self._polling_interval)
+
+            if self._success_count >= self.cycles:
+                break
+
+    def _submit_config(self, config, base_model, mutators):
+        _logger.info('Model submitted to running queue: %s', config)
+        model = get_targeted_model(base_model, mutators, config)
+        submit_models(model)
+        self._running_models.append((config, model))
+        return model
+
+    def _move_succeeded_models_to_population(self):
+        completed_indices = []
+        for i, (config, model) in enumerate(self._running_models):
+            metric = None
+            if self.on_failure == 'worst' and model.status == ModelStatus.Failed:
+                metric = self._worst
+            elif model.status == ModelStatus.Trained:
+                metric = model.metric
+            if metric is not None:
+                individual = Individual(config, metric)
+                _logger.info('Individual created: %s', str(individual))
+                self._population.append(individual)
+                if len(self._population) > self.population_size:
+                    self._population.popleft()
+                completed_indices.append(i)
+        for i in completed_indices[::-1]:
+            # delete from end to start so that the index number will not be affected.
+            self._success_count += 1
+            self._running_models.pop(i)
+
+    def _remove_failed_models_from_running_list(self):
+        # This is only done when on_failure policy is set to "ignore".
+        # Otherwise, failed models will be treated as inf when processed.
+        if self.on_failure == 'ignore':
+            number_of_failed_models = len([g for g in self._running_models if g[1].status == ModelStatus.Failed])
+            self._running_models = [g for g in self._running_models if g[1].status != ModelStatus.Failed]
+            if number_of_failed_models > 0:
+                _logger.info('%d failed models are ignored. Will retry.', number_of_failed_models)
diff --git a/nni/retiarii/strategies/tpe_strategy.py b/nni/retiarii/strategy/tpe_strategy.py
similarity index 91%
rename from nni/retiarii/strategies/tpe_strategy.py
rename to nni/retiarii/strategy/tpe_strategy.py
index 9f0fcd2455..8d823bae11 100644
--- a/nni/retiarii/strategies/tpe_strategy.py
+++ b/nni/retiarii/strategy/tpe_strategy.py
@@ -4,7 +4,7 @@
 from nni.algorithms.hpo.hyperopt_tuner import HyperoptTuner
 
 from .. import Sampler, submit_models, query_available_resources, is_stopped_exec
-from .strategy import BaseStrategy
+from .base import BaseStrategy
 
 _logger = logging.getLogger(__name__)
 
@@ -50,16 +50,14 @@ def run(self, base_model, applied_mutators):
             sample_space.extend(recorded_candidates)
         self.tpe_sampler.update_sample_space(sample_space)
 
-        _logger.info('stargety start...')
+        _logger.info('TPE strategy has been started.')
         while True:
             avail_resource = query_available_resources()
             if avail_resource > 0:
                 model = base_model
-                _logger.info('apply mutators...')
-                _logger.info('mutators: %s', str(applied_mutators))
+                _logger.info('New model created. Applied mutators: %s', str(applied_mutators))
                 self.tpe_sampler.generate_samples(self.model_id)
                 for mutator in applied_mutators:
-                    _logger.info('mutate model...')
                     mutator.bind_sampler(self.tpe_sampler)
                     model = mutator.apply(model)
                 # run models
diff --git a/nni/retiarii/strategy/utils.py b/nni/retiarii/strategy/utils.py
new file mode 100644
index 0000000000..c1055d1707
--- /dev/null
+++ b/nni/retiarii/strategy/utils.py
@@ -0,0 +1,29 @@
+import collections
+from typing import Dict, Any, List
+from ..graph import Model
+from ..mutator import Mutator, Sampler
+
+
+class _FixedSampler(Sampler):
+    def __init__(self, sample):
+        self.sample = sample
+
+    def choice(self, candidates, mutator, model, index):
+        return self.sample[(mutator, index)]
+
+
+def dry_run_for_search_space(model: Model, mutators: List[Mutator]) -> Dict[Any, List[Any]]:
+    search_space = collections.OrderedDict()
+    for mutator in mutators:
+        recorded_candidates, model = mutator.dry_run(model)
+        for i, candidates in enumerate(recorded_candidates):
+            search_space[(mutator, i)] = candidates
+    return search_space
+
+
+def get_targeted_model(base_model: Model, mutators: List[Mutator], sample: dict) -> Model:
+    sampler = _FixedSampler(sample)
+    model = base_model
+    for mutator in mutators:
+        model = mutator.bind_sampler(sampler).apply(model)
+    return model
diff --git a/test/retiarii_test/darts/test.py b/test/retiarii_test/darts/test.py
index bf0fabdada..3c3d6fa37c 100644
--- a/test/retiarii_test/darts/test.py
+++ b/test/retiarii_test/darts/test.py
@@ -5,9 +5,9 @@
 from pathlib import Path
 
 import nni.retiarii.trainer.pytorch.lightning as pl
+import nni.retiarii.strategy as strategy
 from nni.retiarii import blackbox_module as bm
 from nni.retiarii.experiment.pytorch import RetiariiExperiment, RetiariiExeConfig
-from nni.retiarii.strategies import TPEStrategy, RandomStrategy
 from torchvision import transforms
 from torchvision.datasets import CIFAR10
 
@@ -33,9 +33,9 @@
                                 val_dataloaders=pl.DataLoader(test_dataset, batch_size=100),
                                 max_epochs=1, limit_train_batches=0.2)
 
-    simple_startegy = RandomStrategy()
+    simple_strategy = strategy.Random()
 
-    exp = RetiariiExperiment(base_model, trainer, [], simple_startegy)
+    exp = RetiariiExperiment(base_model, trainer, [], simple_strategy)
 
     exp_config = RetiariiExeConfig('local')
     exp_config.experiment_name = 'darts_search'
diff --git a/test/retiarii_test/darts/test_oneshot.py b/test/retiarii_test/darts/test_oneshot.py
index 755f33600c..731d44742c 100644
--- a/test/retiarii_test/darts/test_oneshot.py
+++ b/test/retiarii_test/darts/test_oneshot.py
@@ -8,8 +8,7 @@
 from torchvision import transforms
 from torchvision.datasets import CIFAR10
 
-from nni.retiarii.experiment.pytorch import RetiariiExperiment, RetiariiExeConfig
-from nni.retiarii.strategies import TPEStrategy
+from nni.retiarii.experiment.pytorch import RetiariiExperiment
 from nni.retiarii.trainer.pytorch import DartsTrainer
 
 from darts_model import CNN
diff --git a/test/retiarii_test/mnasnet/test.py b/test/retiarii_test/mnasnet/test.py
index 1158d0ce08..8d07a8afb0 100644
--- a/test/retiarii_test/mnasnet/test.py
+++ b/test/retiarii_test/mnasnet/test.py
@@ -9,7 +9,7 @@
 from nni.retiarii import blackbox_module as bm
 from base_mnasnet import MNASNet
 from nni.retiarii.experiment.pytorch import RetiariiExperiment, RetiariiExeConfig
-from nni.retiarii.strategies import TPEStrategy
+from nni.retiarii.strategy import TPEStrategy
 from torchvision import transforms
 from torchvision.datasets import CIFAR10
 
@@ -46,9 +46,9 @@
         BlockMutator('mutable_1')
     ]
 
-    simple_startegy = TPEStrategy()
+    simple_strategy = TPEStrategy()
 
-    exp = RetiariiExperiment(base_model, trainer, applied_mutators, simple_startegy)
+    exp = RetiariiExperiment(base_model, trainer, applied_mutators, simple_strategy)
 
     exp_config = RetiariiExeConfig('local')
     exp_config.experiment_name = 'mnasnet_search'
diff --git a/test/retiarii_test/mnist/test.py b/test/retiarii_test/mnist/test.py
index 42ca877db1..f215d84d8f 100644
--- a/test/retiarii_test/mnist/test.py
+++ b/test/retiarii_test/mnist/test.py
@@ -1,11 +1,11 @@
 import random
 
 import nni.retiarii.nn.pytorch as nn
+import nni.retiarii.strategy as strategy
 import nni.retiarii.trainer.pytorch.lightning as pl
 import torch.nn.functional as F
 from nni.retiarii import blackbox_module as bm
 from nni.retiarii.experiment.pytorch import RetiariiExeConfig, RetiariiExperiment
-from nni.retiarii.strategies import RandomStrategy
 from torch.utils.data import DataLoader
 from torchvision import transforms
 from torchvision.datasets import MNIST
@@ -42,9 +42,9 @@ def forward(self, x):
                                 val_dataloaders=pl.DataLoader(test_dataset, batch_size=100),
                                 max_epochs=2)
 
-    simple_startegy = RandomStrategy()
+    simple_strategy = strategy.Random()
 
-    exp = RetiariiExperiment(base_model, trainer, [], simple_startegy)
+    exp = RetiariiExperiment(base_model, trainer, [], simple_strategy)
 
     exp_config = RetiariiExeConfig('local')
     exp_config.experiment_name = 'mnist_search'
diff --git a/test/ut/retiarii/test_strategy.py b/test/ut/retiarii/test_strategy.py
new file mode 100644
index 0000000000..5f5fe42208
--- /dev/null
+++ b/test/ut/retiarii/test_strategy.py
@@ -0,0 +1,139 @@
+import random
+import time
+import threading
+from typing import *
+
+import nni.retiarii.execution.api
+import nni.retiarii.nn.pytorch as nn
+import nni.retiarii.strategy as strategy
+import torch
+import torch.nn.functional as F
+from nni.retiarii import Model
+from nni.retiarii.converter import convert_to_graph
+from nni.retiarii.execution import wait_models
+from nni.retiarii.execution.interface import AbstractExecutionEngine, WorkerInfo, MetricData, AbstractGraphListener
+from nni.retiarii.graph import DebugTraining, ModelStatus
+from nni.retiarii.nn.pytorch.mutator import process_inline_mutation
+
+
+class MockExecutionEngine(AbstractExecutionEngine):
+    def __init__(self, failure_prob=0.):
+        self.models = []
+        self.failure_prob = failure_prob
+        self._resource_left = 4
+
+    def _model_complete(self, model: Model):
+        time.sleep(random.uniform(0, 1))
+        if random.uniform(0, 1) < self.failure_prob:
+            model.status = ModelStatus.Failed
+        else:
+            model.metric = random.uniform(0, 1)
+            model.status = ModelStatus.Trained
+        self._resource_left += 1
+
+    def submit_models(self, *models: Model) -> None:
+        for model in models:
+            self.models.append(model)
+            self._resource_left -= 1
+            threading.Thread(target=self._model_complete, args=(model, )).start()
+
+    def query_available_resource(self) -> Union[List[WorkerInfo], int]:
+        return self._resource_left
+
+    def register_graph_listener(self, listener: AbstractGraphListener) -> None:
+        pass
+
+    def trial_execute_graph(cls) -> MetricData:
+        pass
+
+
+def _reset_execution_engine(engine=None):
+    nni.retiarii.execution.api._execution_engine = engine
+
+
+class Net(nn.Module):
+    def __init__(self, hidden_size=32):
+        super(Net, self).__init__()
+        self.conv1 = nn.Conv2d(1, 20, 5, 1)
+        self.conv2 = nn.Conv2d(20, 50, 5, 1)
+        self.fc1 = nn.LayerChoice([
+            nn.Linear(4*4*50, hidden_size, bias=True),
+            nn.Linear(4*4*50, hidden_size, bias=False)
+        ])
+        self.fc2 = nn.LayerChoice([
+            nn.Linear(hidden_size, 10, bias=False),
+            nn.Linear(hidden_size, 10, bias=True)
+        ])
+
+    def forward(self, x):
+        x = F.relu(self.conv1(x))
+        x = F.max_pool2d(x, 2, 2)
+        x = F.relu(self.conv2(x))
+        x = F.max_pool2d(x, 2, 2)
+        x = x.view(-1, 4*4*50)
+        x = F.relu(self.fc1(x))
+        x = self.fc2(x)
+        return F.log_softmax(x, dim=1)
+
+
+def _get_model_and_mutators():
+    base_model = Net()
+    script_module = torch.jit.script(base_model)
+    base_model_ir = convert_to_graph(script_module, base_model)
+    base_model_ir.training_config = DebugTraining()
+    mutators = process_inline_mutation(base_model_ir)
+    return base_model_ir, mutators
+
+
+def test_grid_search():
+    gridsearch = strategy.GridSearch()
+    engine = MockExecutionEngine()
+    _reset_execution_engine(engine)
+    gridsearch.run(*_get_model_and_mutators())
+    wait_models(*engine.models)
+    selection = set()
+    for model in engine.models:
+        selection.add((
+            model.get_node_by_name('_model__fc1').operation.parameters['bias'],
+            model.get_node_by_name('_model__fc2').operation.parameters['bias']
+        ))
+    assert len(selection) == 4
+    _reset_execution_engine()
+
+
+def test_random_search():
+    random = strategy.Random()
+    engine = MockExecutionEngine()
+    _reset_execution_engine(engine)
+    random.run(*_get_model_and_mutators())
+    wait_models(*engine.models)
+    selection = set()
+    for model in engine.models:
+        selection.add((
+            model.get_node_by_name('_model__fc1').operation.parameters['bias'],
+            model.get_node_by_name('_model__fc2').operation.parameters['bias']
+        ))
+    assert len(selection) == 4
+    _reset_execution_engine()
+
+
+def test_evolution():
+    evolution = strategy.RegularizedEvolution(population_size=5, sample_size=3, cycles=10, mutation_prob=0.5, on_failure='ignore')
+    engine = MockExecutionEngine(failure_prob=0.2)
+    _reset_execution_engine(engine)
+    evolution.run(*_get_model_and_mutators())
+    wait_models(*engine.models)
+    _reset_execution_engine()
+
+    evolution = strategy.RegularizedEvolution(population_size=5, sample_size=3, cycles=10, mutation_prob=0.5, on_failure='worst')
+    engine = MockExecutionEngine(failure_prob=0.4)
+    _reset_execution_engine(engine)
+    evolution.run(*_get_model_and_mutators())
+    wait_models(*engine.models)
+    _reset_execution_engine()
+
+
+if __name__ == '__main__':
+    test_grid_search()
+    test_random_search()
+    test_evolution()