npm install babel-plugin-component -D

//babel.config.js 全文內容如下
module.exports = {
  presets: [
    '@vue/cli-plugin-babel/preset'
  ],
  plugins: [
    [
      'component',
      {
        libraryName: 'element-ui',
        styleLibraryName: 'theme-chalk'
      }
    ]
  ]
}

// element.js 全文內容如下，按自己需要引入就好了
import Vue from 'vue'
import {
    Button,
    Form,
    FormItem,
    Input,
    Message,
    Container,
    Header,
    Aside,
    Main,
    Menu,
    Submenu,
    MenuItem,
    Breadcrumb,
    BreadcrumbItem,
    Card,
    Row,
    Col,
    Table,
    TableColumn,
    Switch,
    Tooltip,
    Pagination,
    Dialog,
    MessageBox,
    Tag,
    Tree,
    Select,
    Option,
    Cascader,
    Alert,
    Tabs,
    TabPane
} from 'element-ui'
Vue.use(Button)
Vue.use(Form)
Vue.use(FormItem)
Vue.use(Input)
Vue.use(Container)
Vue.use(Header)
Vue.use(Aside)
Vue.use(Main)
Vue.use(Menu)
Vue.use(Submenu)
Vue.use(MenuItem)
Vue.use(Breadcrumb)
Vue.use(BreadcrumbItem)
Vue.use(Card)
Vue.use(Row)
Vue.use(Col)
Vue.use(Table)
Vue.use(TableColumn)
Vue.use(Switch)
Vue.use(Tooltip)
Vue.use(Pagination)
Vue.use(Dialog)
Vue.use(Tag)
Vue.use(Tree)
Vue.use(Select)
Vue.use(Option)
Vue.use(Cascader)
Vue.use(Alert)
Vue.use(Tabs)
Vue.use(TabPane)
Vue.prototype.$message = Message
Vue.prototype.$confirm = MessageBox.confirm

//main.js 中添加下面這行代碼（路徑和文件名按自己的來）
import './plugins/element.js'

import ElementUI from 'element-ui';
Vue.use(ElementUI);

<template>
<div id="app">
<router-view/>
</div>
</template>
<script>
export default {
}
</script>
<style>
</style>

// The Vue build version to load with the `import` command
// (runtime-only or standalone) has been set in webpack.base.conf with an alias.
import Vue from 'vue'
import App from './App'
import 'element-ui/lib/theme-chalk/index.css'
Vue.config.productionTip = false
/* eslint-disable no-new */
new Vue({
el: '#app',
router,
render: c=> c(App)
})

// The Vue build version to load with the `import` command
// (runtime-only or standalone) has been set in webpack.base.conf with an alias.
import Vue from 'vue'
import App from './App'
import router from './router'
import ElementUI from 'element-ui'
import 'element-ui/lib/theme-chalk/index.css'
Vue.config.productionTip = false
Vue.use(ElementUI)
/* eslint-disable no-new */
new Vue({
  el: '#app',
  router,
  render: c => c(App)
})