The impact resistance of protective structure directly affects the vitality of the ship. Since the excellent energy absorption characteristics and lightweight structural forms, foamed aluminum sandwich panels have gradually replaced stiffened panels and are widely used in local structures and components of vessels. In order to improve the protective ability of the ship structure, the impact resistance of the foam aluminum sandwich panel is studied in this paper. The deformation mechanism of the foam aluminum sandwich panel under the impact of the foam aluminum projectile is simulated by the finite element analysis, and the effect of different core thickness and core strength on the dynamic response of the sandwich panel is studied. An optimized structural form is proposed for the shear failure of foam aluminum sandwich panels. The results show that the optimized structure improves the impact resistance of foam aluminum sandwich panel and the shear resistance of the intermediate core layer. The research of this paper provides reference for the optimization of foam metal sandwich structure and its application in ship protection structure.