Metal 3D printing technology has become one of the most potential and promising industrial manufacturing technologies. Through laser selective sintering (SLS) technology, reasonable sintering parameters are selected to sinter metal powder. Complex three-dimensional models of porous scaffolds with different pore sizes were established, and porous scaffold stress and strain distribution were simulated by using finite element analysis. The optimized three-dimensional model of porous scaffolds was obtained. The theoretical basis for subsequent experimental analysis was established. Then 316L stainless steel porous scaffolds were prepared by SLS technology. The porous scaffolds were tested by post-heat treatment, compression and metallographic experiments. The mechanical properties, hardness tests and surface microstructures of the specimens were analyzed. Through the simulation analysis, the optimized pore size of the porous scaffold was obtained, and a porous scaffold which is more suitable for the weight bearing of the human bone defect site was obtained, which can guide the subsequent research. It was found that the strength and modulus of elasticity of 300μm porous scaffolds were higher than those of natural bone. Metal parts with porous structure ensured the biomechanical properties of bone prostheses and had good mechanical properties.