<el-dropdown 
                    class="nav_item"
                    :class="activeIndex == 2 ? 'active' : ''" 
                >
                      <span class="el-dropdown-link cursor">
                        账号交易<i class="el-icon-arrow-down el-icon--right"></i>
                      </span>
                      <el-dropdown-menu slot="dropdown" style="width: 150px;text-align: center;" :append-to-body="false">
                        <el-dropdown-item>
                            <router-link to="/gameList">我要买号</router-link>
                        </el-dropdown-item>
                        <el-dropdown-item>
                            <router-link to="/account/pushAccount">我要卖号</router-link>
                           </el-dropdown-item>
                        <el-dropdown-item>
                            <router-link to="/recyle">号商回收</router-link>
                        </el-dropdown-item>
                     </el-dropdown-menu>
                </el-dropdown>

.el-dropdown-menu {
          position: absolute !important;
          top: 0px !important;
          left: 0px !important;
    }