<tr class="font12" v-for="(item, index) in OrderAuditDiscountList.list" :key="index"
  :class="OrderAuditDiscountList.list.length - 1 == index ? 'blodfont' : ''">

 其中： :class="OrderAuditDiscountList.list.length - 1 == index ? 'blodfont' : ''"

.blodfont {
  background: #FDF5F4;
  font-weight: bold;
}