diff --git a/README.md b/README.md
index c7637d8d..545f8700 100644
--- a/README.md
+++ b/README.md
@@ -159,7 +159,7 @@ TEST_TIMEOUT=2000 egg-bin test
 
 ### cov
 
-Using [istanbul] to run code coverage, it support all test params above.
+Using [nyc] to run code coverage, it support all test params above.
 
 Coverage reporter will output text-summary, json and lcov.
 
@@ -169,6 +169,7 @@ You can pass any mocha argv.
 
 - `-x` add dir ignore coverage, support multiple argv
 - `--prerequire` prerequire files for coverage instrument, you can use this options if load files slowly when call `mm.app` or `mm.cluster`
+- `--typescript` / `--ts` enable typescript support, default to `false`, if true, will auto add `.ts` extension and ignore `typings` and `d.ts`.
 - also support all test params above.
 
 #### environment
diff --git a/lib/cmd/cov.js b/lib/cmd/cov.js
index 94e027e0..45410a02 100644
--- a/lib/cmd/cov.js
+++ b/lib/cmd/cov.js
@@ -104,8 +104,17 @@ class CovCommand extends Command {
       '-r', 'json-summary',
       '-r', 'json',
       '-r', 'lcov',
+      '--extension', '.ts',
     ];
 
+    // typescript support
+    if (context.typescript) {
+      covArgs.push('--extension');
+      covArgs.push('.ts');
+      this.addExclude('typings/');
+      this.addExclude('**/*.d.ts');
+    }
+
     for (const exclude of this[EXCLUDES]) {
       covArgs.push('-x');
       covArgs.push(exclude);
diff --git a/test/fixtures/example-ts/app/controller/home.ts b/test/fixtures/example-ts/app/controller/home.ts
new file mode 100644
index 00000000..a860bc79
--- /dev/null
+++ b/test/fixtures/example-ts/app/controller/home.ts
@@ -0,0 +1,9 @@
+'use strict';
+
+import { Controller } from 'egg';
+
+export default class HomeController extends Controller {
+  public async index() {
+    this.ctx.body = 'hi, egg';
+  }
+}
diff --git a/test/fixtures/example-ts/app/router.ts b/test/fixtures/example-ts/app/router.ts
index 46c83b7d..f8cf3f6f 100644
--- a/test/fixtures/example-ts/app/router.ts
+++ b/test/fixtures/example-ts/app/router.ts
@@ -1,9 +1,7 @@
 'use strict';
 
-import { Application, Context } from 'egg';
+import { Application } from 'egg';
 
 export default (app: Application) => {
-  app.router.get('/', function* (this: Context) {
-    this.body = `hi, egg`;
-  });
+  app.router.get('/', app.controller.home.index);
 };
\ No newline at end of file
diff --git a/test/fixtures/example-ts/typings/app/controller/index.d.ts b/test/fixtures/example-ts/typings/app/controller/index.d.ts
new file mode 100644
index 00000000..de6b5d46
--- /dev/null
+++ b/test/fixtures/example-ts/typings/app/controller/index.d.ts
@@ -0,0 +1,10 @@
+// This file was auto created by egg-ts-helper
+// Do not modify this file!!!!!!!!!
+
+import Home from '../../../app/controller/home';
+
+declare module 'egg' {
+  interface IController {
+    home: Home;
+  }
+}
diff --git a/test/fixtures/example-ts/typings/index.d.ts b/test/fixtures/example-ts/typings/index.d.ts
new file mode 100644
index 00000000..f7e4b522
--- /dev/null
+++ b/test/fixtures/example-ts/typings/index.d.ts
@@ -0,0 +1,7 @@
+import { Context } from 'egg';
+
+// extend egg
+declare module 'egg' {
+  interface Context {
+  }
+}
\ No newline at end of file
diff --git a/test/ts.test.js b/test/ts.test.js
index 2038b91c..9f6f3ede 100644
--- a/test/ts.test.js
+++ b/test/ts.test.js
@@ -61,4 +61,19 @@ describe('test/ts.test.js', () => {
       .expect('code', 0)
       .end();
   });
+
+  it('should cov app', () => {
+    if (process.env.EGG_VERSION && process.env.EGG_VERSION === '1') {
+      console.log('skip egg@1');
+      return;
+    }
+    cwd = path.join(__dirname, './fixtures/example-ts');
+    return coffee.fork(eggBin, [ 'cov', '--ts' ], { cwd })
+      // .debug()
+      .expect('stdout', /hi, egg, 123456/)
+      .expect('stdout', /should work/)
+      .expect('stdout', /Statements.*100%/)
+      .expect('code', 0)
+      .end();
+  });
 });