我自己努力了，然后再次阅读文档。在这里它说明：

I struggled with this myself, then went to read through the documentation again. Here what it states:

• scrollOverflow :(默认false）定义是否创建
  滚动该部分，以防其内容大于其高度
  。如果设置为true，它需要供应商插件
  jquery.slimscroll.min，它应该在 fullPaje.js
  插件之前加载。例如：

• scrollOverflow: (default false) defines whether or not to create a scroll for the section in case its content is bigger than the height of it. In case of setting it to true, it requieres the vendor plugin jquery.slimscroll.min and it should be loaded before the fullPaje.js plugin. For example:

<script type="text/javascript" src="vendors/jquery.slimscroll.min.js"></script>
<script type="text/javascript" src="jquery.fullPage.js"></script>

未加载SlimScroll.js是这里的问题。

Not loading SlimScroll.js was the issue here.

然后相应地设置$ .fn.fullpage（{}）配置。

Then set your $.fn.fullpage({ }) config accordingly.

$('#fullpage').fullpage({
    scrollOverflow: true
});