diff --git a/python/paddle/fluid/contrib/slim/quantization/post_training_quantization.py b/python/paddle/fluid/contrib/slim/quantization/post_training_quantization.py
index 73d1e31159a6f496fb5269e7f064fc2b52c73538..c959fc29bc91865cb5cc1b5c08aae47584bf8ad3 100644
--- a/python/paddle/fluid/contrib/slim/quantization/post_training_quantization.py
+++ b/python/paddle/fluid/contrib/slim/quantization/post_training_quantization.py
@@ -476,7 +476,7 @@ class PostTrainingQuantization(object):
 
         self._reset_activation_persistable()
 
-        if self._algo is 'min_max':
+        if self._algo == 'min_max':
             self._save_input_threhold()
         else:
             self._update_program()