diff --git a/gin.go b/gin.go
index becdf08..cf324d5 100644
--- a/gin.go
+++ b/gin.go
@@ -36,4 +36,5 @@ const (
 	GinEnvField                = "env"                      // 环境变量
 	GinRequestSuccess          = "gin_request_success"      // 请求成功
 	GinLogicAfterResponseKey   = "__logic_after_response__" // gin请求成功后, 执行的逻辑
+	GinTraceInstanceField      = "__trace_instance__"       // trace实例的key
 )