Abstract: In order to obtain the influence of processing technology on the mechanical properties and penetration performance of high strength 15-5PH steel, selective laser melting (SLM) and forging process were selected to process projectiles. The effects of three SLM manufacturing processes and forging process on the properties of 15-5PH steel were compared and analyzed by means of mirror observation, quasi-static, SHPB and concrete penetration. The results show that SLM technology refines the grains of 15-5PH steel, and the mechanical properties of 15-5PH steel formed by SLM are improved. The improvement effect of SLM-B process is more obvious. The quasi-static yield strength of 15-5PH steel formed by SLM-B can be enhanced 13.1 % than that of forging process. The tensile strength can be increased by 15.8 % compared with the forging process. Compared with the forging process steel, the dynamic yield strength can be increased by 9.0 %. And the SLM-B process can provide the best anti-wear performance for the projectile. The experimental results show that the SLM process can improve the mechanical properties and wear resistance of 15-5PH steel.