Hi Dear friendsi have large amount of closed polygons with different sizes,the task is assign the numbers(text) to all polygons,but here different sizes of polygons,so the text will be placed inside,or out side of the polygons,is any easy way or any tool to place the text in side and center of the polygons automatically,

As far as I know, you won't do that in Autodesk environment, while it's doable thru the opensource Qgis, sir.
:)

A custom lisp routine might be able to handle the task but I'm not 100% sure.

Try going to the AutoDesk Customization Forum, and Searching.  There are probably several threads about just this kind of thing.