Abstract: Based on the existing structure of personal rapid transit (PRT) system, the structural lightweight optimization of the bogie frame is studied. By using the SIMP (solid isotropic material with penalization) in relative density method for topology optimization, the running wheel seat and the thickness size of the main plate beam position of the frame are improved, the simulation results of them before and after optimization are compared and analyzed. Through adjusting the frame parameters according to the optimized stress and strain results in different areas of the framework, the optimized parameters are controlled to achieve the overall optimization results under the premise of considering the actual structure and functional structure of the frame. The results show that the volume of the optimized area is greatly reduced, the lightweight result is obvious, and the overall structural strength is good, all can meet the requirements of train safe operation under the worst condition.