diff --git a/docs/en/guide.md b/docs/en/guide.md
index f0c97e77912e..8e04701b5b88 100644
--- a/docs/en/guide.md
+++ b/docs/en/guide.md
@@ -307,7 +307,7 @@ Sometimes we have the need to load middleware on a specific route. In previous v
 Now you can provide a middleware in you application (any directory)，such as `src/app/middleware/api.ts`.
 
 ```ts
-import { WebMiddleware } from 'midway';
+import { Middleware, WebMiddleware, provide } from 'midway';
 
 @provide()
 export class ApiMiddleware implements WebMiddleware {
@@ -316,7 +316,7 @@ export class ApiMiddleware implements WebMiddleware {
   helloConfig;
 
   resolve() {
-    return async (ctx, next) => {
+    return async (ctx, next): Middleware => {
       ctx.api = '222' + this.helloConfig.b;
       await next();
     };
diff --git a/docs/guide.md b/docs/guide.md
index 8c90ab4b1c9d..07bcd5fbcc5f 100644
--- a/docs/guide.md
+++ b/docs/guide.md
@@ -317,7 +317,7 @@ export class HomeController {
 现在可以提供一个 middleware（任意目录），比如 `src/app/middleware/api.ts`。
 
 ```ts
-import { WebMiddleware } from 'midway';
+import { Middleware, WebMiddleware, provide } from 'midway';
 
 @provide()
 export class ApiMiddleware implements WebMiddleware {
@@ -326,7 +326,7 @@ export class ApiMiddleware implements WebMiddleware {
   helloConfig;
 
   resolve() {
-    return async (ctx, next) => {
+    return async (ctx, next): Middleware => {
       ctx.api = '222' + this.helloConfig.b;
       await next();
     };