解决方法:将变化应用到几何形状本身而不是Path

 <Path Data="M 0 0 20 100 30 0 40 100 50 100 60 0" Stroke="Black" Canvas.Top="20">
<Path.RenderTransform>
<ScaleTransform ScaleX="3" ScaleY="1"/>
</Path.RenderTransform>
</Path>

调整为

<Path Stroke="Black" Canvas.Top="40" >
<Path.Data>
<PathGeometry Figures="M 0 0 20 100 30 0 40 100 50 100 60 0" >
<PathGeometry.Transform>
<ScaleTransform ScaleX="3" ScaleY="2"></ScaleTransform>
</PathGeometry.Transform>
</PathGeometry>
</Path.Data>
</Path>

参考

留待后查,同时方便他人