<el-form-item label="藕粉桂花糖糕" prop="state" required><el-selectref="mySelect"v-model="form.state"style="width: 280px"placeholder="请选择"><el-option label="藕粉" :value="1" /><el-option label="桂花" :value="2" /><el-option label="糖糕" :value="3" /></el-select>
</el-form-item>

解决办法：使用 toggleMenu() 方法 

created() {// 用之前得 this.$nextTick，需要 dom 存在才好使this.$nextTick(() => {this.$refs.mySelect.toggleMenu()})
},