diff --git a/src/runtime/test/host_port_test.cpp b/src/runtime/test/host_port_test.cpp
index cb290d41b7..ae049cedfa 100644
--- a/src/runtime/test/host_port_test.cpp
+++ b/src/runtime/test/host_port_test.cpp
@@ -263,7 +263,7 @@ TEST(host_port_test, dns_resolver)
 
 void send_and_check_host_port_by_serialize(const host_port &hp, dsn_msg_serialize_format t)
 {
-    auto hp_str = hp.to_std_string();
+    const auto &hp_str = hp.to_std_string();
     ::dsn::rpc_address server("localhost", 20101);
 
     dsn::message_ptr msg_ptr = dsn::message_ex::create_request(RPC_TEST_THRIFT_HOST_PORT_PARSER);