To alleviate the stress shielding effect caused by the implantation of the traditional femoral stem, the TPMS structure with better affinity for the biological cell is selected as the porous structure of the femoral stem. The TPMS structure sample can be formed better through SLM technology. The compression test results show that the mechanical properties of the three common TPMS porous structures can meet the requirements on the use of femoral stems within the constraints of bone growth and SLM equipment manufacturing. Compared with the G and D structures, the P structure shows greater comprehensive advantage in manufacturability and ability to adjust. It is a porous structure more suitable for the design of the femoral stem. The results of finite element analysis show that the peak stress of the P structure femoral stem does not exceed the yield strength of porous materials under common daily active loads, which proves that the application of P structure in the femoral stem can meet the needs of daily activities. Moreover, after the introduction of P structure in the femoral stem, the stress distribution of the corresponding femur is significantly improved, which can effectively alleviate the stress shielding effect. Among these, the P structure with a porosity of 75% is the best, which can reduce the stress shielding rate by 41.83 percentage points. This is beneficial in improving the long-term stability and service life of the prosthesis after implantation.