diff --git a/constants.go b/constants.go
index a42c25e..1b90101 100644
--- a/constants.go
+++ b/constants.go
@@ -9,9 +9,11 @@ import (
 
 var (
 	ServletSocketKey = cuc.ContextKey("ServletSocket")
-	ClientTypeKey    = cuc.ContextKey("ClientType")
-	SocketIDKey      = cuc.ContextKey("SocketID")
-	TargetIDKey      = cuc.ContextKey("TargetID")
+
+	GRPCMetadataKey = cuc.ContextKey("GRPCMetadata")
+	ClientTypeKey   = cuc.ContextKey("ClientType")
+	SocketIDKey     = cuc.ContextKey("SocketID")
+	TargetIDKey     = cuc.ContextKey("TargetID")
 )
 
 const (
diff --git a/internal/server/rpc/gateway_rpc_servlet_handlers.go b/internal/server/rpc/gateway_rpc_servlet_handlers.go
index 9f42e19..fb86dae 100644
--- a/internal/server/rpc/gateway_rpc_servlet_handlers.go
+++ b/internal/server/rpc/gateway_rpc_servlet_handlers.go
@@ -24,11 +24,17 @@ type GatewayRPCServletHandlers struct {
 }
 
 func (sh *GatewayRPCServletHandlers) Invoke(servletCTX rpc.ServletContext, requestCodec protocol.RegistryCodec) (result interface{}, err error) {
-	md := metadata.Pairs(
-		oogw.GRPCClientTypeKey, servletCTX.GetAttribute(oogw.SocketIDKey).(string),
-		oogw.GRPCSessionIDKey, servletCTX.GetAttribute(oogw.SocketIDKey).(string),
-		oogw.GRPCTargetIDKey, servletCTX.GetAttribute(oogw.SocketIDKey).(string))
-	grpcCTX := metadata.NewOutgoingContext(context.Background(), md)
+	md := servletCTX.GetAttribute(oogw.GRPCMetadataKey)
+	if nil == md {
+		md = metadata.Pairs(
+			oogw.GRPCClientTypeKey, servletCTX.GetAttribute(oogw.SocketIDKey).(string),
+			oogw.GRPCSessionIDKey, servletCTX.GetAttribute(oogw.SocketIDKey).(string),
+			oogw.GRPCTargetIDKey, servletCTX.GetAttribute(oogw.SocketIDKey).(string))
+
+		servletCTX.SetAttribute(oogw.GRPCMetadataKey, md)
+	}
+
+	grpcCTX := metadata.NewOutgoingContext(context.Background(), md.(metadata.MD))
 
 	params, err := requestCodec.Params()
 	if nil != err {