增加sticky-top样式
<view class="sticky-top">
<u-tabs @change="changePackStatus" height="84" font-size="28" name="cate_name" bar-width="60" bar-height="4"
active-color="#EB9309" count="cate_count" :list="list" :is-scroll="false" :current="current"></u-tabs>
<view class="search-box">
<u-search search-icon="/static/images/search.png" :show-action="false" bg-color="#F5F5F5" placeholder="搜索订单号或备注"
@change="search" v-model="keyword"></u-search>
</view>
</view>
.sticky-top{
position: sticky;
top: 0;
left: 0;
right: 0;
width: 100%;
z-index: 1;
}