diff --git a/python/paddle/fluid/tests/unittests/dist_transformer.py b/python/paddle/fluid/tests/unittests/dist_transformer.py
index 23abd7953f96735b447aa9edde62a848db5367fb..27c67edf4f62dd3c5d396826348f8da4513667ba 100644
--- a/python/paddle/fluid/tests/unittests/dist_transformer.py
+++ b/python/paddle/fluid/tests/unittests/dist_transformer.py
@@ -1159,7 +1159,7 @@ def prepare_encoder(src_word,
             name=pos_enc_param_name,
             trainable=False,
             initializer=fluid.initializer.ConstantInitializer(0.001)))
-    str_pos_enc.stop_gradient = True
+    src_pos_enc.stop_gradient = True
     enc_input = src_word_emb + src_pos_enc
     return layers.dropout(
         enc_input,