diff --git a/autokeras/blocks/__init__.py b/autokeras/blocks/__init__.py
index a73020ea3..51a1e2389 100644
--- a/autokeras/blocks/__init__.py
+++ b/autokeras/blocks/__init__.py
@@ -41,14 +41,15 @@
 from autokeras.blocks.wrapper import StructuredDataBlock
 from autokeras.blocks.wrapper import TextBlock
 from autokeras.blocks.wrapper import TimeseriesBlock
+from autokeras.utils import utils
 
 
 def serialize(obj):
-    return keras.utils.serialize_keras_object(obj)
+    return utils.serialize_keras_object(obj)
 
 
 def deserialize(config, custom_objects=None):
-    return keras.utils.deserialize_keras_object(
+    return utils.deserialize_keras_object(
         config,
         module_objects=globals(),
         custom_objects=custom_objects,
diff --git a/autokeras/hyper_preprocessors.py b/autokeras/hyper_preprocessors.py
index 10252181d..6b239e744 100644
--- a/autokeras/hyper_preprocessors.py
+++ b/autokeras/hyper_preprocessors.py
@@ -11,18 +11,18 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from tensorflow import keras
 
 from autokeras import preprocessors
 from autokeras.engine import hyper_preprocessor
+from autokeras.utils import utils
 
 
 def serialize(encoder):
-    return keras.utils.serialize_keras_object(encoder)
+    return utils.serialize_keras_object(encoder)
 
 
 def deserialize(config, custom_objects=None):
-    return keras.utils.deserialize_keras_object(
+    return utils.deserialize_keras_object(
         config,
         module_objects=globals(),
         custom_objects=custom_objects,
diff --git a/autokeras/nodes.py b/autokeras/nodes.py
index 7b86b59c9..99ebc1bf9 100644
--- a/autokeras/nodes.py
+++ b/autokeras/nodes.py
@@ -28,14 +28,15 @@
 from autokeras import preprocessors
 from autokeras.engine import io_hypermodel
 from autokeras.engine import node as node_module
+from autokeras.utils import utils
 
 
 def serialize(obj):
-    return keras.utils.serialize_keras_object(obj)
+    return utils.serialize_keras_object(obj)
 
 
 def deserialize(config, custom_objects=None):
-    return keras.utils.deserialize_keras_object(
+    return utils.deserialize_keras_object(
         config,
         module_objects=globals(),
         custom_objects=custom_objects,
diff --git a/autokeras/preprocessors/__init__.py b/autokeras/preprocessors/__init__.py
index 8691e36df..db6d88faf 100644
--- a/autokeras/preprocessors/__init__.py
+++ b/autokeras/preprocessors/__init__.py
@@ -24,14 +24,15 @@
 from autokeras.preprocessors.encoders import OneHotEncoder
 from autokeras.preprocessors.postprocessors import SigmoidPostprocessor
 from autokeras.preprocessors.postprocessors import SoftmaxPostprocessor
+from autokeras.utils import utils
 
 
 def serialize(preprocessor):
-    return keras.utils.serialize_keras_object(preprocessor)
+    return utils.serialize_keras_object(preprocessor)
 
 
 def deserialize(config, custom_objects=None):
-    return keras.utils.deserialize_keras_object(
+    return utils.deserialize_keras_object(
         config,
         module_objects=globals(),
         custom_objects=custom_objects,
diff --git a/autokeras/utils/utils.py b/autokeras/utils/utils.py
index 9552b9e54..d707f1f97 100644
--- a/autokeras/utils/utils.py
+++ b/autokeras/utils/utils.py
@@ -138,3 +138,23 @@ def add_to_hp(hp, hps, name=None):
     class_name = hp.__class__.__name__
     func = getattr(hps, class_name)
     return func(name=name, **kwargs)
+
+
+def serialize_keras_object(obj):
+    if hasattr(tf.keras.utils, "legacy"):
+        return tf.keras.utils.legacy.serialize_keras_object(obj)  # pragma: no cover
+    else:
+        return tf.keras.utils.serialize_keras_object(obj)
+
+
+def deserialize_keras_object(
+    config, module_objects=None, custom_objects=None, printable_module_name=None
+):
+    if hasattr(tf.keras.utils, "legacy"):
+        return tf.keras.utils.legacy.deserialize_keras_object(  # pragma: no cover
+            config, custom_objects, module_objects, printable_module_name
+        )
+    else:
+        return tf.keras.utils.deserialize_keras_object(
+            config, custom_objects, module_objects, printable_module_name
+        )