diff --git a/mace/python/tools/converter_tool/caffe_converter.py b/mace/python/tools/converter_tool/caffe_converter.py
index 8ce0a0741d6b791aa16c4137b297521280e93109..3ff2fa231e2b461481a41c966b65831a78c955bc 100644
--- a/mace/python/tools/converter_tool/caffe_converter.py
+++ b/mace/python/tools/converter_tool/caffe_converter.py
@@ -324,12 +324,17 @@ class CaffeConverter(base_converter.ConverterInterface):
                 global_pooling_arg.i = 1
 
     def convert_ops(self):
+        layer_names = set()
         for layer in self._caffe_layers.layer:
             caffe_op = self._caffe_net.get_op(layer.name)
             if caffe_op not in self._skip_ops:
+                mace_check(layer.name not in layer_names,
+                           "There is duplicate layer name '%s' in your model"
+                           % layer.name)
                 mace_check(layer.type in self._op_converters,
                            "Mace does not support caffe op type %s yet"
                            % layer.type)
+                layer_names.add(layer.name)
                 self._op_converters[layer.type](caffe_op)
 
     def add_tensor(self, name, shape, data_type, value):
diff --git a/mace/python/tools/converter_tool/shape_inference.py b/mace/python/tools/converter_tool/shape_inference.py
index 9478a3e545f9dc203ea01f03b1d32a4452ad964b..da6541f499459532e9ead7b277cb1192a9b3fdd1 100644
--- a/mace/python/tools/converter_tool/shape_inference.py
+++ b/mace/python/tools/converter_tool/shape_inference.py
@@ -81,7 +81,8 @@ class ShapeInference(object):
     def infer_shape_general(self, op):
         if len(op.input) > 0:
             mace_check(op.input[0] in self._output_shape_cache,
-                       "%s does not exist" % op.input[0])
+                       "Op %s input %s does not exist"
+                       % (op.name, op.input[0]))
             input_shape = self._output_shape_cache[op.input[0]]
             self.add_output_shape(op, [input_shape])