diff --git a/ppdet/core/workspace.py b/ppdet/core/workspace.py
index 03c53df58a9d00feb1578b46dfb4eeaf345a519e..d7074a1f43418c13abdedebf4ea4f3bf76104de7 100644
--- a/ppdet/core/workspace.py
+++ b/ppdet/core/workspace.py
@@ -139,7 +139,7 @@ def merge_config(config, another_cfg=None):
     #       batch size config to global, models can get batch size config
     #       from global config when building model.
     #       batch size in evaluation or inference can also be added here
-    if 'TrainReader' in dct:
+    if 'TrainReader' in dct and 'batch_size' in dct['TrainReader']:
         dct['train_batch_size'] = dct['TrainReader']['batch_size']
 
     return dct