diff --git a/python/tools/tf_converter.py b/python/tools/tf_converter.py
index 5ea9db4b39313877d6f0e4de8d6627c78ad02185..0da5420fd954646679511335647d63a63867c1c1 100644
--- a/python/tools/tf_converter.py
+++ b/python/tools/tf_converter.py
@@ -34,7 +34,9 @@ def main(unused_args):
     output_graph_def = tf_dsp_converter_lib.convert_to_mace_pb(
       input_graph_def, FLAGS.input_node, FLAGS.output_node, FLAGS.dsp_mode)
   else:
-    input_shape = [int(x) for x in FLAGS.input_shape.split(',')]
+    input_shape = []
+    if FLAGS.input_shape != "":
+      input_shape.extend([int(x) for x in FLAGS.input_shape.split(',')])
     output_graph_def = tf_converter_lib.convert_to_mace_pb(
       input_graph_def, FLAGS.input_node, input_shape, FLAGS.output_node,
       FLAGS.data_type, FLAGS.runtime, FLAGS.winograd)
@@ -129,7 +131,7 @@ def parse_args():
   parser.add_argument(
     "--input_shape",
     type=str,
-    default="1,512,512,3",
+    default="",
     help="input shape.")
   return parser.parse_known_args()
 
diff --git a/python/tools/tf_converter_lib.py b/python/tools/tf_converter_lib.py
index d221bc54dc2661ea19f307d163ecafc4093fcb94..bf714231efd4a0a491af41e34a615254489b0e3e 100644
--- a/python/tools/tf_converter_lib.py
+++ b/python/tools/tf_converter_lib.py
@@ -4,10 +4,8 @@ import numpy as np
 import math
 import copy
 from lib.python.tools import memory_optimizer
-from tensorflow.core.framework import attr_value_pb2
 from tensorflow.core.framework import graph_pb2
 from tensorflow.core.framework import tensor_shape_pb2
-from tensorflow.core.framework import node_def_pb2
 
 # TODO: support NCHW formt, now only support NHWC.
 padding_mode = {