diff --git a/x2paddle/convert.py b/x2paddle/convert.py
index cadd9fd9d6a0b246c3efced681031e9596587566..792d8dc7f2ca746902591950ca7d84f84aebcb2c 100644
--- a/x2paddle/convert.py
+++ b/x2paddle/convert.py
@@ -300,7 +300,7 @@ def onnx2paddle(model_path,
 
     from x2paddle.decoder.onnx_decoder import ONNXDecoder
     from x2paddle.op_mapper.onnx2paddle.onnx_op_mapper import ONNXOpMapper
-    model = ONNXDecoder(model_path, input_shape_dict, enable_onnx_checker)
+    model = ONNXDecoder(model_path, enable_onnx_checker, input_shape_dict)
     mapper = ONNXOpMapper(model)
     mapper.paddle_graph.build()
     logging.info("Model optimizing ...")
diff --git a/x2paddle/decoder/onnx_decoder.py b/x2paddle/decoder/onnx_decoder.py
index f51be83573ec17e3c6cf11be41c6a600752b9430..7fe4696d49685ce0c5d8a8b8fe7ff5de051edea2 100755
--- a/x2paddle/decoder/onnx_decoder.py
+++ b/x2paddle/decoder/onnx_decoder.py
@@ -173,7 +173,7 @@ class ONNXGraphDataNode(GraphNode):
 
 
 class ONNXGraph(Graph):
-    def __init__(self, onnx_model, input_shape_dict):
+    def __init__(self, onnx_model, input_shape_dict=None):
         super(ONNXGraph, self).__init__(onnx_model)
         self.fixed_input_shape = {}
         if input_shape_dict is not None:
@@ -395,7 +395,7 @@ class ONNXGraph(Graph):
 
 
 class ONNXDecoder(object):
-    def __init__(self, onnx_model, input_shape_dict, enable_onnx_checker):
+    def __init__(self, onnx_model, enable_onnx_checker, input_shape_dict=None):
         onnx_model = onnx.load(onnx_model)
         print('model ir_version: {}, op version: {}'.format(
             onnx_model.ir_version, onnx_model.opset_import[0].version))