New material which absorbs impact energy effectively and has excellent mechanical property is developed. The used amount is increased at automobile field day by day. Aluminum foam with various air sell lattices within is one of representative porosity metals which are used at many automobile parts because it has the excellent lightness and impact energy absorption function. For this reason, aluminum foam is used widely as a component among composite materials. This study aims to investigate systematically the mechanical property of foam through computer simulation. In order to obtain the property of aluminum foam, aluminum foam is designed as the dimension of 100mm × 100mm × 25mm and the striker that has the diameter of 12.5mm is supposed to impact aluminum foam with impact energies of 6J, 10J, and 14J. Aluminum foam is not penetrated when striker given by energy of 6J or 10J impacts into it, but aluminum foam is penetrated by striker in case of impact energy of 14J. The result can provide the basic data in order to develop the advanced composite material.