diff --git a/pkg/controller/subnet.go b/pkg/controller/subnet.go
index 88c77fa0b31..96de2e5fce2 100644
--- a/pkg/controller/subnet.go
+++ b/pkg/controller/subnet.go
@@ -432,7 +432,7 @@ func checkAndUpdateGateway(subnet *kubeovnv1.Subnet) (bool, error) {
 	switch {
 	case subnet.Spec.Gateway == "":
 		gw, err = util.GetGwByCidr(subnet.Spec.CIDRBlock)
-	case util.CheckProtocol(subnet.Spec.Gateway) != util.CheckProtocol(subnet.Spec.CIDRBlock):
+	case subnet.Spec.Protocol == kubeovnv1.ProtocolDual && util.CheckProtocol(subnet.Spec.Gateway) != util.CheckProtocol(subnet.Spec.CIDRBlock):
 		gw, err = util.AppendGwByCidr(subnet.Spec.Gateway, subnet.Spec.CIDRBlock)
 	default:
 		gw = subnet.Spec.Gateway