diff --git a/PaddleNLP/lexical_analysis/utils.py b/PaddleNLP/lexical_analysis/utils.py
index e3085fe0e788f8979d6e0dddc8d56c85446b8c3f..2513d1285e60aee15ed60f79aa593e70528146ac 100644
--- a/PaddleNLP/lexical_analysis/utils.py
+++ b/PaddleNLP/lexical_analysis/utils.py
@@ -49,7 +49,10 @@ def to_str(string, encoding="utf-8"):
             return string.decode(encoding)
     elif sys.version_info.major == 2:
         if isinstance(string, unicode):
-            return string.encode(encoding)
+            if os.name == 'nt':
+                return string
+            else:
+                return string.encode(encoding)
     return string