1、安装两个依赖

"postcss-pxtorem": "^5.1.1",
"amfe-flexible": "^2.2.1",

2、创建vue.config.js (如果有不需要创建)
const autoprefixer = require("autoprefixer");

const pxtorem = require("postcss-pxtorem");

module.exports = {

css: {

loaderOptions: {

  postcss: {

    plugins: [

      autoprefixer(),

      pxtorem({

        rootValue: 20,

        propList: ["*"]

      })

    ]

  }

}

}

};

px 转 rem