<el-submenu index="1">

            <template slot="title"><i class="el-icon-message"></i>导航一</template>

            <el-menu-item-group>

            <el-menu-item index="1-1">选项1</el-menu-item>

            <el-menu-item index="1-2">选项2</el-menu-item>

            <el-menu-item index="1-3">选项3</el-menu-item>

            </el-menu-item-group>

            <el-submenu index="1-4">

            <template slot="title">选项4</template>

            <el-menu-item index="1-4-1">选项4-1</el-menu-item>

            </el-submenu>

        </el-submenu>

         <el-submenu index="2">

            <template slot="title"><i class="el-icon-menu"></i>导航二</template>

            <el-menu-item-group>

            <template slot="title">分组一</template>

            <el-menu-item index="2-1">选项1</el-menu-item>

            <el-menu-item index="2-2">选项2</el-menu-item>

            </el-menu-item-group>

            <el-menu-item-group title="分组2">

            <el-menu-item index="2-3">选项3</el-menu-item>

            </el-menu-item-group>

            <el-submenu index="2-4">

            <template slot="title">选项4</template>

            <el-menu-item index="2-4-1">选项4-1</el-menu-item>

            </el-submenu>

        </el-submenu>

        <el-submenu index="3">

            <template slot="title"><i class="el-icon-setting"></i>导航三</template>

            <el-menu-item-group>

            <template slot="title">分组一</template>

            <el-menu-item index="3-1">选项1</el-menu-item>

            <el-menu-item index="3-2">选项2</el-menu-item>

            </el-menu-item-group>

            <el-menu-item-group title="分组2">

            <el-menu-item index="3-3">选项3</el-menu-item>

            </el-menu-item-group>

            <el-submenu index="3-4">

            <template slot="title">选项4</template>

            <el-menu-item index="3-4-1">选项4-1</el-menu-item>

            </el-submenu>

        </el-submenu>

        <el-submenu index="4">

            <template slot="title"><i class="el-icon-setting"></i>导航四</template>

            <el-menu-item-group>

            <template slot="title">分组一</template>

            <el-menu-item index="4-1">选项1</el-menu-item>

            <el-menu-item index="4-2">选项2</el-menu-item>

            </el-menu-item-group>

            <el-menu-item-group title="分组2">

            <el-menu-item index="4-3">选项3</el-menu-item>

            </el-menu-item-group>

            <el-submenu index="4-4">

            <template slot="title">选项4</template>

            <el-menu-item index="4-4-1">选项4-1</el-menu-item>

            </el-submenu>

        </el-submenu>