You should be loading the swf's into a movieclip, so you can resize that movieclip after the swf has been loaded. You should be using the MovieClipLoader class so that you can have a listener to determine when loading is complete. You will need something inside the loaded swf to indicate what its normal dimensions are so that you can scale it accordingly. When the file loading is complete, you check the normal dimension info and use it to change the _xscale and _yscale properties of the movieclip.
thnx Ned Murphy
but can my parent SWF (Sample.swf) resize with loaded SWF WxH
id my Sample.swf Wxh is 300x300
and when load 2.swf @ that time can my Sample.swf WxH possible to resize with 400x400
The parent can resize the movieclip after it has been loaded, not before. So you need to load the movie using the MovieClipLoader class so that you can assign a listener to determine when it has finished loading. If you look up MovieClipLoader.addListener in the help documents there is an example there that shows how to detect when the file has been loaded.