In order to analyze the performance of the electric motorcycle frame structure under working condition of vibration and reduce its weight,the transient finite element analysis model is developed with the theory of transient dynamics,and frame dynamic strength is calculated to obtain the maximum stress and stress distribution of frame under the working condition. On that basis,we establish the optimum model with the target function of the frame’s weight based on the optimal module of Hyperworks,and make optimization design of the frame under intensity and rigidity constraint conditions. The theory analysis and experimental results indicate that the frame has surplus strength and the value of safety factor is high under working condition of vibration ,and the strength of the optimized frame meets the requirements of safety and manufacturing process,meanwhile,the weight of frame is reduced by 12.1%,which shows that the optimization method is reliable and effective for the design of the structure of the frame.