Bullet-proof vest is "can absorb and dissipate kinetic energy warheads, fragments, preventing penetration, effective protection of the protective parts of a garment". From the perspective of using, bullet-proof vests can be divided into two types: police and military. From the perspective of material, bullet-proof vests can be divided into software, hardware, and software and hardware complex of three. Soft body armor materials mainly dominated by high performance fibers, these high performance fiber than ordinary material energy absorption capacity given bullet-proof vests bulletproof function, and because of this bullet-proof vests used textile structures, and therefore has considerable flexibility, referred to as soft body armor. Hard body armor is a special type of steel plate, super strong aluminum alloy metal or rigid non-metallic materials such as alumina and silicon carbide bullet-proof material, made of bullet-proof vests are unlikely to have flexibility.