Abstract: Aiming at the problem of structural strength redundancy in the frame of an electric moped （hereinafter referred to as “electric moped”）, a lightweight method based on geometric optimization analysis was proposed. On the basis of establishing the finite element model of the electric moped frame, the optimization model is established. The optimal design variables of the frame are determined by the geometric optimization analysis method, and the optimal section size is sought based on the thickness optimization strategy. The maximum static strength Von Mises stress of the optimized frame is within the range of the restricted allowable stress. After optimization, the weight of the electric moped body is reduced by 23% compared with that before optimization, achieving the lightest weight of the body, and meeting the needs of the speed, power and endurance of the electric moped while achieving the goal of “double carbon”.