The lightweight design is considered to be an effective way to save energy and reduce emissions. Therefore, a lightweight design method for the axle under different working conditions is proposed based on the ANSYS workbench. Firstly, the forces on the axle were analyzed under different working conditions. Secondly, a three-dimensional model of the axle is established using Pro/E, and then imported into the workbench to simulate the static analysis based on the results of the mechanical calculation. The stress, displacement, and safety factors of the axle are obtained by material parameter adding, finite element grid division, boundary condition constraints, and loading conditions. Finally, based on the simulation data results of the axle, the structure of the axle is optimized, the model is compared again, and a lightweight design scheme can be obtained. The results show that the mass of the axle is reduced by 13.14 kg, and its strength and stiffness meet the required conditions. The lightweight design method can save materials, reduce production costs, and cut carbon emissions, which has extremely important reference and practical significance for the lightweight design of axles and similar products.