diff --git a/dtmcli/dtmimp/consts.go b/dtmcli/dtmimp/consts.go
index 95757ac..54586af 100644
--- a/dtmcli/dtmimp/consts.go
+++ b/dtmcli/dtmimp/consts.go
@@ -55,4 +55,9 @@ const (
 
 	// XaBarrier1 const for xa barrier id
 	XaBarrier1 = "01"
+
+	// ProtocolGRPC const for protocol grpc
+	ProtocolGRPC = "grpc"
+	// ProtocolHTTP const for protocol http
+	ProtocolHTTP = "http"
 )
diff --git a/dtmsvr/trans_class.go b/dtmsvr/trans_class.go
index 5023e06..bedb590 100644
--- a/dtmsvr/trans_class.go
+++ b/dtmsvr/trans_class.go
@@ -31,7 +31,7 @@ func (t *TransGlobal) setupPayloads() {
 		}
 	}
 	if t.Protocol == "" {
-		t.Protocol = "http"
+		t.Protocol = dtmimp.ProtocolHTTP
 	}
 
 }
diff --git a/dtmsvr/trans_status.go b/dtmsvr/trans_status.go
index 2d78241..6184c2f 100644
--- a/dtmsvr/trans_status.go
+++ b/dtmsvr/trans_status.go
@@ -89,7 +89,7 @@ func (t *TransGlobal) getURLResult(uri string, branchID, op string, branchPayloa
 	if uri == "" { // empty url is success
 		return nil
 	}
-	if t.Protocol == "http" || strings.HasPrefix(uri, "http://") || strings.HasPrefix(uri, "https://") {
+	if t.Protocol == dtmimp.ProtocolHTTP || strings.HasPrefix(uri, "http://") || strings.HasPrefix(uri, "https://") {
 		if t.RequestTimeout != 0 {
 			dtmimp.RestyClient.SetTimeout(time.Duration(t.RequestTimeout) * time.Second)
 		}
@@ -146,7 +146,7 @@ func (t *TransGlobal) getURLResult(uri string, branchID, op string, branchPayloa
 		}
 		return dtmimp.RespAsErrorCompatible(resp)
 	}
-	dtmimp.PanicIf(t.Protocol == "http", fmt.Errorf("bad url for http: %s", uri))
+	dtmimp.PanicIf(t.Protocol == dtmimp.ProtocolHTTP, fmt.Errorf("bad url for http: %s", uri))
 	// grpc handler
 	server, method, err := dtmdriver.GetDriver().ParseServerMethod(uri)
 	if err != nil {