Abstract: Drive axle is the terminal of vehicle transmission system，and it bears major function，such as transferring large torque，connecting with driving wheel and driving vehicle.Because of its special using requirements，there are special structure and technology in many aspects，such as design，machining and heat treatment process and structure.Starting from the production of typical fault line case，3D finite element analysis method was used to verify the design of drive axle strength and rationality，improve the defects，reduce design risk and shorten design cycle.