Changing the illustration size

[NicBoy]

When I import the illustration file as a composition to aftereffects its so small,

But, When I import the PNG file to aftereffects, thats in a good size!

How I can change the size of illustration main file in illustrator? So I can use it in a high quality in aftereffects

[Mylenium]

That entirely depends how you work and export in AI. You can change the document settings globally, you can resize the artboard(s) and fit them to selected objects, you can export selected objects only. And of course in all that your unit settings and DPI matter. You may want to read the AI online help on soem of these basics.

Mylenium