diff --git a/.travis.yml b/.travis.yml
index 5ec1467..faeb0c0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,7 +3,9 @@ language: node_js
 node_js:
   - '4'
   - '6'
-  - '7'
+  - '8'
+  - '10'
+  - '11'
 install:
   - npm i npminstall && npminstall
 script:
diff --git a/README.md b/README.md
index 190be1e..dddaf53 100644
--- a/README.md
+++ b/README.md
@@ -46,7 +46,8 @@ Patch locales functions to koa app.
   - {String} defaultLocale: default locale. Optional, default is `en-US`.
   - {String} queryField: locale field name on query. Optional, default is `locale`.
   - {String} cookieField: locale field name on cookie. Optional, default is `locale`.
-  - {Object} localeAlias: locale value map. Optional, default is {}.
+  - {String} cookieDomain: domain on cookie. Optional, default is `''`.
+  - {Object} localeAlias: locale value map. Optional, default is `{}`.
   - {String|Number} cookieMaxAge: set locale cookie value max age. Optional, default is `1y`, expired after one year.
 
 ```js
diff --git a/appveyor.yml b/appveyor.yml
index 2efd0fa..a231e55 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -2,7 +2,9 @@ environment:
   matrix:
     - nodejs_version: '4'
     - nodejs_version: '6'
-    - nodejs_version: '7'
+    - nodejs_version: '8'
+    - nodejs_version: '10'
+    - nodejs_version: '11'
 
 install:
   - ps: Install-Product node $env:nodejs_version
@@ -11,6 +13,6 @@ install:
 test_script:
   - node --version
   - npm --version
-  - npm run ci
+  - npm run test
 
 build: off
diff --git a/index.js b/index.js
index 4ead61e..006c84a 100644
--- a/index.js
+++ b/index.js
@@ -27,6 +27,7 @@ module.exports = function (app, options) {
   const defaultLocale = formatLocale(options.defaultLocale);
   const queryField = options.queryField;
   const cookieField = options.cookieField;
+  const cookieDomain = options.cookieDomain;
   const localeAlias = options.localeAlias;
   const writeCookie = options.writeCookie;
   const cookieMaxAge = ms(options.cookieMaxAge);
@@ -194,12 +195,14 @@ module.exports = function (app, options) {
     // if header not send, set the locale cookie
     if (writeCookie && cookieLocale !== locale && !this.headerSent) {
       // locale change, need to set cookie
-      this.cookies.set(cookieField, locale, {
+      const cookieOptions = {
         // make sure brower javascript can read the cookie
         httpOnly: false,
         maxAge: cookieMaxAge,
         signed: false,
-      });
+        domain: cookieDomain,
+      };
+      this.cookies.set(cookieField, locale, cookieOptions);
       debugSilly('Saved cookie with locale %s', locale);
     }
     debug('Locale: %s from %s', locale, localeOrigin);
diff --git a/package.json b/package.json
index 28e2c85..84052dc 100644
--- a/package.json
+++ b/package.json
@@ -30,7 +30,7 @@
     "istanbul": "*",
     "koa": "^1.2.4",
     "mm": "^2.0.0",
-    "mocha": "*",
+    "mocha": "4",
     "pedding": "^1.1.0",
     "supertest": "^2.0.1"
   },
@@ -41,8 +41,7 @@
     "web": "https://github.com/koajs/locales"
   },
   "bugs": {
-    "url": "https://github.com/koajs/locales/issues",
-    "email": "m@fengmk2.com"
+    "url": "https://github.com/koajs/locales/issues"
   },
   "keywords": [
     "koa-locales",
@@ -55,8 +54,8 @@
     "node": ">=4.0.0"
   },
   "ci": {
-    "version": "4, 6, 7"
+    "version": "4, 6, 8, 10, 11"
   },
-  "author": "fengmk2 <m@fengmk2.com> (https://fengmk2.com)",
+  "author": "fengmk2 <fengmk2@gmail.com> (https://fengmk2.com)",
   "license": "MIT"
 }
diff --git a/test/index.test.js b/test/index.test.js
index fee29e4..d4c145a 100644
--- a/test/index.test.js
+++ b/test/index.test.js
@@ -35,7 +35,7 @@ describe('koa-locales.test.js', function () {
         'gender': 'model.user.fields.gender',
         'name': 'model.user.fields.name',
       })
-      .expect('Set-Cookie', /^locale=en\-us; path=\/; expires=\w+/)
+      .expect('Set-Cookie', /^locale=en\-us; path=\/; expires=[^;]+ GMT$/)
       .expect(200, done);
     });
 
@@ -50,6 +50,37 @@ describe('koa-locales.test.js', function () {
     });
   });
 
+  describe('options.cookieDomain', function () {
+    const app = createApp({
+      cookieDomain: '.foo.com',
+    });
+
+    it('should use default locale: en-US', function (done) {
+      request(app.callback())
+      .get('/')
+      .expect({
+        email: 'Email',
+        hello: 'Hello fengmk2, how are you today?',
+        message: 'Hello fengmk2, how are you today? How was your 18.',
+        empty: '',
+        notexists_key: 'key not exists',
+        empty_string: '',
+        empty_value: 'emptyValue',
+        novalue: 'key %s ok',
+        arguments3: '1 2 3',
+        arguments4: '1 2 3 4',
+        arguments5: '1 2 3 4 5',
+        arguments6: '1 2 3 4 5. 6',
+        values: 'foo bar foo bar {2} {100}',
+        object: 'foo bar foo bar {z}',
+        'gender': 'model.user.fields.gender',
+        'name': 'model.user.fields.name',
+      })
+      .expect('Set-Cookie', /^locale=en\-us; path=\/; expires=[^;]+; domain=.foo.com$/)
+      .expect(200, done);
+    });
+  });
+
   describe('custom options', function () {
     const app = createApp({
       dirs: [__dirname + '/locales', __dirname + '/other-locales'],