The purpose of this article is studying the behavior of lightweight composites under metallic projectile by stress wave and comparing the results with numerical simulations. The target includes external layer, Alumina ceramic layer and supportive layer. The impact velocity of the projectile is 500 m/s. In this article, two lightweight composite targets with polymeric supportive layer and metallic supportive layer are studied. The results of numerical simulations and classic theory of stress wave propagation are in good agreement. The effect of changing supportive layer material and time of stress wave propagation into layers by the results of modeling is also studied.