试了网上的一些方法都没有成功，最后，我在cmd中检测了一下dot的版本，才发现问题。具体操作是：
打开cmd 运行：dot -v 出现问题：There is no layout engine support for “dot”… 运行：dot -c 没有提示（成功） 再次运行dot -v 结果如下图（成功）。详情也可参考：win10安装Graphviz 再次执行上述测试代码，没有报错，nice~
(base) PS C:\Users\HiFuture> dot -v dot - graphviz version 2.44.1 (20200629.0846) There is no layout engine support for "dot" Perhaps "dot -c" needs to be run (with installer's privileges) to register the plugins? (base) PS C:\Users\HiFuture> dot -c (base) PS C:\Users\HiFuture> dot -v dot - graphviz version 2.44.1 (20200629.0846) libdir = "D:\software\Graphvz2.44.1\Graphviz 2.44.1\bin" Activated plugin library: gvplugin_dot_layout.dll Using layout: dot:dot_layout Activated plugin library: gvplugin_core.dll Using render: dot:core Using device: dot:dot:core The plugin configuration file: D:\software\Graphvz2.44.1\Graphviz 2.44.1\bin\config6 was successfully loaded. render : cairo dot dot_json fig gdiplus json json0 map mp pic ps svg tk vml xdot xdot_json layout : circo dot fdp neato nop nop1 nop2 osage patchwork sfdp twopi textlayout : textlayout device : bmp canon cmap cmapx cmapx_np dot dot_json emf emfplus eps fig gif gv imap imap_np ismap jpe jpeg jpg json json0 metafile mp pdf pic plain plain-ext png ps ps2 svg tif tiff tk vml xdot xdot1.2 xdot1.4 xdot_json loadimage : (lib) bmp eps gif jpe jpeg jpg png ps svg