diff --git a/python/paddle/fluid/dygraph/dygraph_to_static/utils.py b/python/paddle/fluid/dygraph/dygraph_to_static/utils.py
index c664cc986db20..dbd5dc800d392 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 @@ def visit(self, node):
 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.