diff --git a/caffe2fluid/convert.py b/caffe2fluid/convert.py
index 95bafb877af2b0085d96400ad27cc2c018a91a3a..adce7d0ef3cffe8c72c1c0a6fad29e3d092c9e39 100755
--- a/caffe2fluid/convert.py
+++ b/caffe2fluid/convert.py
@@ -41,8 +41,12 @@ def convert(def_path, caffemodel_path, data_output_path, code_output_path,
                 np.save(data_out, data)
         if code_output_path:
             print_stderr('Saving source...')
+            s = sys.version
             with open(code_output_path, 'wb') as src_out:
-                src_out.write(str.encode(transformer.transform_source()))
+                if s.startswith('2'):
+                    src_out.write(transformer.transform_source())
+                else:
+                    src_out.write(str.encode(transformer.transform_source()))
         print_stderr('set env variable before using converted model '\
                 'if used custom_layers:')
         custom_pk_path = os.path.dirname(os.path.abspath(__file__))