diff --git a/tensorflow2fluid/src/convert.py b/tensorflow2fluid/src/convert.py
index 5c1c3740fc140acbd12990977d23b1a15985b7ec..2a1bfe6b72ae0b5f846c9815e38025239c067dd2 100644
--- a/tensorflow2fluid/src/convert.py
+++ b/tensorflow2fluid/src/convert.py
@@ -38,6 +38,9 @@ def _convert(args):
         for i in range(len(items)):
             if items[i] != "None":
                 items[i] = int(items[i])
+            else:
+                items[i] = None
+                
         input_shape.append(items)
 
     sys.stderr.write("\nLoading tensorflow model......\n")