Hello linfeng413,
Well, the best resource and examples of how to use the Windows SDK can be found on Microsoft's website. In particular, you can find more information on the ShowWindow function on the following
MSDN page. I would suspect that you will need to iterate through the open application windows, find the Matlab window, get the handle for this window, then call the ShowWindow function with the SW_HIDE parameter.
Thanks
Wendy L
LabWindows/CVI Developer Newsletter