diff --git a/paddleseg/cvlibs/config.py b/paddleseg/cvlibs/config.py
index 0cefb55701..4f924f324a 100644
--- a/paddleseg/cvlibs/config.py
+++ b/paddleseg/cvlibs/config.py
@@ -158,12 +158,14 @@ def lr_scheduler(self) -> paddle.optimizer.lr.LRScheduler:
         if 'warmup_iters' in params:
             use_warmup = True
             warmup_iters = params.pop('warmup_iters')
+            assert 'warmup_start_lr' in params, "Please set warmup_start_lr in lr_scheduler"
             warmup_start_lr = params.pop('warmup_start_lr')
             end_lr = params['learning_rate']
 
         lr_type = params.pop('type')
         if lr_type == 'PolynomialDecay':
-            params.setdefault('decay_steps', self.iters)
+            iters = self.iters - warmup_iters if use_warmup else self.iters
+            params.setdefault('decay_steps', iters)
             params.setdefault('end_lr', 0)
             params.setdefault('power', 0.9)
         lr_sche = getattr(paddle.optimizer.lr, lr_type)(**params)