<style lang="scss" scoped>
.upload-demo ::v-deep .el-upload--picture-card{
  margin-top: 4%;
  height:80px;
  width:80px;
  line-height: 80px;
}
.upload-demo ::v-deep .el-upload-list--picture-card .el-upload-list__item{
  margin-top: 4%;
  height:80px;
  width:80px;
  line-height: 80px;
}
</style>

需要使用::v-deep才行