https://www.cnblogs.com/zdd2017/p/11065429.html

<el-form
     ref="form"
    :rules="formRules"
    :inline="true"
    :model="form"
    label-width="80px"
>
    <!-- 固定项目 -->
    <el-form-item label="姓名" prop="name">
        <el-input v-model="form.name" palceholder="请输入姓名">
        </el-input>
    </el-form-item>
    <el-form-item label="手机号" prop="phone">
        <el-input v-model="form.phone" palceholder="请输入手机号">
        </el-input>
    </el-form-item>
</el-form>
<el-button @click="addItem" type="primary">增加</el-button>

export default {
  name: 'dynamicForm',
  data () {
    return {
      form: {
        name: '',
        phone: ''
      },
      formRules: {
        name: [{required: true, message: '请输入姓名', trigger: 'blur'}],
        phone: [
          {required: true, message: '请输入手机号', trigger: 'blur'},
          { pattern: /^1[34578]\d{9}$/, message: '目前只支持中国大陆的手机号码' }
        ]
      }
    }
  }
}

动态表单部分：

<!-- 动态增加项目 -->
<!-- 不止一个项目，用div包裹起来 -->
<div v-for="(item, index) in form.dynamicItem" :key="index">
    <el-form-item
        label="姓名"
        :prop="'dynamicItem.' + index + '.name'"
        :rules="{
            required: true, message: '姓名不能为空', trigger: 'blur'
        }"
    >
        <el-input v-model="item.name"></el-input>
    </el-form-item>
    <el-form-item
        label="手机号"
        :prop="'dynamicItem.' + index + '.phone'"
        :rules="[
             {required: true, message: '手机号不能为空', trigger: 'blur'},
             { pattern: /^1[34578]\d{9}$/, message: '目前只支持中国大陆的手机号码' }
          ]"
        >
        <el-input v-model="item.phone"></el-input>
    </el-form-item>
    <el-form-item>
        <i class="el-icon-delete" @click="deleteItem(item, index)"></i>
    </el-form-item>
</div>

在data 的 form 里增加 dynamicItem

form: {
        name: '',
        phone: '',
        dynamicItem: []
}

在methods里增加方法

methods: {
    addItem () {
      this.form.dynamicItem.push({
        name: '',
        phone: ''
      })
    },
    deleteItem (item, index) {
      this.form.dynamicItem.splice(index, 1)
    }
}