diff --git a/src/plugin/advancedFormat/index.js b/src/plugin/advancedFormat/index.js
--- a/src/plugin/advancedFormat/index.js
+++ b/src/plugin/advancedFormat/index.js
@@ -13,7 +13,7 @@ export default (o, c, d) => { // locale needed later
     const locale = this.$locale()
     const utils = this.$utils()
     const str = formatStr || FORMAT_DEFAULT
-    const result = str.replace(/\[([^\]]+)]|Q|wo|gggg|Do|X|x|k{1,2}|S/g, (match) => {
+    const result = str.replace(/\[([^\]]+)]|Q|wo|ww|w|gggg|Do|X|x|k{1,2}|S/g, (match) => {
       switch (match) {
         case 'Q':
           return Math.ceil((this.$M + 1) / 3)
@@ -23,6 +23,9 @@ export default (o, c, d) => { // locale needed later
           return this.weekYear()
         case 'wo':
           return locale.ordinal(this.week(), 'W') // W for week
+        case 'w':
+        case 'ww':
+          return utils.s(this.week(), match === 'w' ? 1 : 2, '0')
         case 'k':
         case 'kk':
           return utils.s(String(this.$H === 0 ? 24 : this.$H), match === 'k' ? 1 : 2, '0')

diff --git a/test/plugin/weekOfYear.test.js b/test/plugin/weekOfYear.test.js
--- a/test/plugin/weekOfYear.test.js
+++ b/test/plugin/weekOfYear.test.js
@@ -2,8 +2,10 @@ import moment from 'moment'
 import MockDate from 'mockdate'
 import dayjs from '../../src'
 import weekOfYear from '../../src/plugin/weekOfYear'
+import advancedFormat from '../../src/plugin/advancedFormat'
 import '../../src/locale/en-gb'
 
+dayjs.extend(advancedFormat)
 dayjs.extend(weekOfYear)
 
 beforeEach(() => {
@@ -39,3 +41,10 @@ it('Week of year with locale', () => {
   expect(dayjs('2018-12-30').week()).toBe(moment('2018-12-30').week())
   expect(dayjs('2019-12-29').week()).toBe(moment('2019-12-29').week())
 })
+
+it('Format w ww wo', () => {
+  const day = '2019-07-28'
+  const D = dayjs(day)
+  const M = moment(day)
+  expect(D.format('w ww wo')).toBe(M.format('w ww wo'))
+})

dayjs().format('YYYY w Week') error result
**Describe the bug**
使用dayjs().format('YYYY年第w周') 期望可以得到 2019年第29周

**Expected behavior**
使用dayjs().format('YYYY年第w周') 期望可以得到 2019年第29周，实际上却展示为2019年第w周

**Information**
 - Day.js 版本1.8.16
 - OS: Linux
 - Browser   chrome  74.0.3729.131
 - Time zone: GMT+08:00


Bug confirmed.

Current workaround 
```
var dayjs = require("dayjs")
var advancedFormat = require('dayjs/plugin/advancedFormat')
var weekOfYear = require('dayjs/plugin/weekOfYear')

dayjs.extend(advancedFormat)
dayjs.extend(weekOfYear)


dayjs().format('YYYY年第wo周')

```
test/timezone.test.js(1) test/timezone.test.js(2) test/timezone.test.js(3) test/timezone.test.js(4)
test/plugin/weekOfYear.test.js