Unlike element UI, element plus does not use node sass or dart sass, but sass and sass loader. At first, I thought it might be that the sass version and sass loader version of the project are inconsistent with the version of element plus, so I deleted the version of my project and installed the version consistent with the version used by element plus, but the problem is not solved. The version is as follows:

 "devDependencies": {
    "postcss-loader": "^5.3.0",
    "sass": "^1.35.1",
    "sass-loader": "^10.0.1",
  }

After tossing around for a while, I found an article on the Internet (the solution of icon garbled code packaged by dart sass compiled element UI). This is a solution for element UI, but I don’t know whether it is effective for element plus. Therefore, after using this method for element plus according to the instructions, I found that it is also effective, so I made a record, The steps are as follows:
1. Install the plug-in CSS Unicode loader;

yarn add css-unicode-loader -D //npm install css-unicode-loader -D

2. In vue.config.js configuration, I used the object writing method, and here it is modified to function writing method

// vue.config.js
module.exports = {
  configureWebpack: config => {
    config.module.rules.filter(rule => {
      return rule.test.toString().indexOf("scss") !== -1;
    }).forEach(rule => {
        rule.oneOf.forEach(oneOfRule => {
          oneOfRule.use.splice(oneOfRule.use.indexOf(require.resolve('sass-loader')), 0,
          	{ loader: require.resolve("css-unicode-loader")})
        })
      })
    }
}