diff --git a/backend/init/router/router.go b/backend/init/router/router.go
index 750ea65f6d0d..e1c4eae898dd 100644
--- a/backend/init/router/router.go
+++ b/backend/init/router/router.go
@@ -28,9 +28,9 @@ var (
 )
 
 func toIndexHtml(c *gin.Context) {
+	c.Writer.Header().Set("Content-Type", "text/html; charset=utf-8")
 	c.Writer.WriteHeader(http.StatusOK)
 	_, _ = c.Writer.Write(web.IndexByte)
-	c.Writer.Header().Add("Accept", "text/html")
 	c.Writer.Flush()
 }
 
@@ -131,9 +131,9 @@ func setWebStatic(rootRouter *gin.RouterGroup) {
 				handleNoRoute(c)
 				return
 			}
+			c.Writer.Header().Set("Content-Type", "text/html; charset=utf-8")
 			c.Writer.WriteHeader(http.StatusOK)
 			_, _ = c.Writer.Write(web.IndexByte)
-			c.Writer.Header().Add("Accept", "text/html")
 			c.Writer.Flush()
 		})
 	}