Abstract: The response of ship structure and the effectiveness of various armor structure under ballistic impact of small caliber artillery were studied experimentally. Ballistic impact experiment was carried out to simulate the impact of typical warhead of small caliber artillery. Projectile and 6 kinds of targets were designed according to the similarity theory of ballistic impact. The results show that the structure of ship cannot resist the attack from small caliber artillery, and special armor needs to be equipped. The combination armor of ceramic, steel, fiber reinforced composite can save 60% approximately in weight, compared with steel armor. The use of ceramic can change the failure mode and extent of steel back plate, and greatly improve its energy absorpation. In addition, ceramic can erode, mushroom and crash the projectile, those can greatly degrade its penetration performance.