diff --git a/python/paddle/fluid/dygraph/dygraph_to_static/utils.py b/python/paddle/fluid/dygraph/dygraph_to_static/utils.py
index c664cc986db20ca19dc098e9f22a25f8e5811f8f..dbd5dc800d3925c6aa3295c3d8f947a3267ac722 100644
--- a/python/paddle/fluid/dygraph/dygraph_to_static/utils.py
+++ b/python/paddle/fluid/dygraph/dygraph_to_static/utils.py
@@ -92,7 +92,7 @@ FOR_ITER_VAR_NAME_PREFIX = '__for_loop_iter_var'
 FOR_ITER_ZIP_TO_LIST_PREFIX = '__for_loop_iter_zip'
 
 RE_PYNAME = '[a-zA-Z0-9_]+'
-RE_PYMODULE = '[a-zA-Z0-9_]+\.'
+RE_PYMODULE = r'[a-zA-Z0-9_]+\.'
 
 # FullArgSpec is valid from Python3. Defined a Namedtuple to
 # to make it available in Python2.