diff --git a/protocol/tun/inbound.go b/protocol/tun/inbound.go
index 730f68509..26b024b9e 100644
--- a/protocol/tun/inbound.go
+++ b/protocol/tun/inbound.go
@@ -335,7 +335,7 @@ func (t *Inbound) Start(stage adapter.StartStage) error {
 			outboundManager := service.FromContext[adapter.OutboundManager](t.ctx)
 			endpointManager := service.FromContext[adapter.EndpointManager](t.ctx)
 			for _, outbound := range outboundManager.Outbounds() {
-				if _, isFlowOutbound := outbound.(adapter.FlowOutbound); isFlowOutbound {
+				if _, isFlowOutbound := outbound.(adapter.FlowOutbound); isFlowOutbound && common.Contains(outbound.Network(), N.NetworkTCP) {
 					if C.IsLinux {
 						t.tunOptions.GSO = true
 					} else {
@@ -345,7 +345,7 @@ func (t *Inbound) Start(stage adapter.StartStage) error {
 				}
 			}
 			for _, endpoint := range endpointManager.Endpoints() {
-				if _, isFlowOutbound := endpoint.(adapter.FlowOutbound); isFlowOutbound {
+				if _, isFlowOutbound := endpoint.(adapter.FlowOutbound); isFlowOutbound && common.Contains(endpoint.Network(), N.NetworkTCP) {
 					if C.IsLinux {
 						t.tunOptions.GSO = true
 					} else {