diff --git a/lib/extend/controller.js b/lib/extend/controller.js
index 1a30ff45..a05ae5a7 100644
--- a/lib/extend/controller.js
+++ b/lib/extend/controller.js
@@ -1,5 +1,5 @@
 const helper = require('think-helper');
-
+const debug = require('debug')('thinkjs');
 const deprecate = require('depd')('thinkjs');
 
 /**
@@ -145,13 +145,19 @@ module.exports = {
    * @param {Mixed} value 
    */
   header(name, value){
+    if(value === undefined && helper.isString(name)){
+      return this.ctx.header[name];
+    }
+    if(this.ctx.res.headersSent){
+      debug(`headers has already sent, url: ${this.ctx.url}`);
+      return;
+    }
     if(value !== undefined){
       return this.ctx.set(name, value);
     }
     if(helper.isObject(name)){
       return this.ctx.set(name);
     }
-    return this.ctx.header[name];
   },
   /**
    * get userAgent header