谢邀，看别人实现效果，css的话比较好查看。打开chrome去查看元素，看它的样式是受什么css控制的。

.icon {
    filter: url(data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg'><filter id=… 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0'/></filter></svg>#grayscale);
    filter: progid: DXImageTransform.Microsoft.BasicImage(grayscale=1);
    -webkit-filter: grayscale(1);
}

/* line 943, ../src/css/_layout.scss */
section#clients .clientLogo span img {
  filter: grayscale(100%);
  -webkit-filter: grayscale(100%);
  -moz-filter: grayscale(100%);
  -o-filter: grayscale(100%);
  -webkit-transition: -webkit-filter 0.8s;
  -moz-transition: -moz-filter 0.8s;
  -o-transition: -o-filter 0.8s;
  transition: filter 0.8s;
  margin: 0 auto;
  max-height: 45px;
  max-width: 200px;
}
/* line 957, ../src/css/_layout.scss */
section#clients .clientLogo span:hover img {
  filter: grayscale(0%);
  -webkit-filter: grayscale(0%);
  -moz-filter: grayscale(0%);
  -o-filter: grayscale(0%);
}

查看源css