Abstract: Process parameters are important factors affecting the molding rate and performance of additive manufacturing parts.Therefore,optimizing process parameters is essential to improve the physical and mechanical properties of additively manufactured parts.In this paper,the effects of different process parameters on the mechanical properties and defects of 316L stainless steel samples prepared by selective laser melting(SLM)are studied through experiments and simulations.The experimental results show that the increase in the scan spacing leads to a decrease in the density of the specimen when other parameters remain constant,and more unfused defects are observed at this time.Finally,it was determined that the optimal molding process combination of SLM 316L stainless steel was 200W laser power,700mm/s scanning speed and 0.04mm scanning spacing,and the density of molded parts was 98.86％under this parameter.