i want to change the shape of wx.TextCtrl widget used in wxpython. normal by default shape is a square box but i want to make all the corner having round curve.
This is not supported by the wx.TextCtrl out of the box. What you need to understand is that most of the core widgets are actually using the operating system's widgets and not drawing them itself. So if the native widget doesn't support this sort of thing, then wxPython's core widgets won't either.
You would need to create a custom widget that you draw yourself to get this functionality. Check out the wxPython demo for examples of custom widgets. All of the widgets in AGW are custom, for example.