diff --git a/parser/onnx/onnx_parser.cc b/parser/onnx/onnx_parser.cc
index 3a88315..75472a2 100644
--- a/parser/onnx/onnx_parser.cc
+++ b/parser/onnx/onnx_parser.cc
@@ -671,13 +671,12 @@ Status OnnxModelParser::ParseAllNodeProto(ge::onnx::GraphProto &onnx_graph, ge::
 }
 
 Status OnnxModelParser::GetGraphInputs(ge::onnx::GraphProto &onnx_graph, std::vector<ge::Operator> &input_ops) {
-  if (input_node_names_.empty()) {
-    // subgraph might not have input, we use constant nodes as the start nodes of graph
-    for (int i = 0; i < onnx_graph.node_size(); i++) {
-      ge::onnx::NodeProto *node = onnx_graph.mutable_node(i);
-      if (node->op_type() == kOpTypeConstant) {
-        input_node_names_.emplace_back(node->name());
-      }
+  // subgraph might not have input, or isolated const nodes exist in the graph,
+  // we use constant nodes as the start nodes of graph
+  for (int i = 0; i < onnx_graph.node_size(); i++) {
+    ge::onnx::NodeProto *node = onnx_graph.mutable_node(i);
+    if (node->op_type() == kOpTypeConstant) {
+      input_node_names_.emplace_back(node->name());
     }
   }
   for (auto in_name : input_node_names_) {
diff --git a/tests/ut/parser/testcase/onnx_parser_testcase/onnx_parser_unittest.cc b/tests/ut/parser/testcase/onnx_parser_testcase/onnx_parser_unittest.cc
index 64669cc..6fdee9e 100644
--- a/tests/ut/parser/testcase/onnx_parser_testcase/onnx_parser_unittest.cc
+++ b/tests/ut/parser/testcase/onnx_parser_testcase/onnx_parser_unittest.cc
@@ -703,4 +703,23 @@ TEST_F(UtestOnnxParser, onnx_test_TransNodeToOperator_SetTensorData)
   EXPECT_EQ(ret, SUCCESS);
 }
 
+TEST_F(UtestOnnxParser, onnx_test_const_input_op)
+{
+  ge::onnx::ModelProto model_proto;
+  ge::onnx::GraphProto* graph = model_proto.mutable_graph();
+  ge::onnx::NodeProto *node_proto = graph->add_node();
+  node_proto->set_op_type("Constant");
+  node_proto->set_domain("const.onnx");
+  node_proto->set_name("const_11");
+  ge::OpDescPtr op_desc_src = std::make_shared<ge::OpDesc>("Constant", "const.onnx");
+  ge::Operator op = ge::OpDescUtils::CreateOperatorFromOpDesc(op_desc_src);
+  std::string op_type = "Constant";
+
+  OnnxModelParser onnx_parser;
+  std::vector<ge::Operator> input_ops;
+  onnx_parser.name_operator_["const_11"] = op;
+  Status ret = onnx_parser.GetGraphInputs(*graph, input_ops);
+  EXPECT_EQ(ret, SUCCESS);
+  EXPECT_EQ(input_ops.size() > 0, true);
+}
 } // namespace ge