Based on DEFORM-3D, the copper bus bar CONFORM extending-forming process was simulated and velocity field, temperature field, stress/ strain field of forming process for 40 mm×10 mm copper bus bar is acquired. According to the analytic results, the effect factors of metal flowing were summed up, and the die design of 50 mm×6 mm copper bus bar was optimized. Compared to the former simulated result, the copper bus bar extruded is filled in order, the flowing stress is quite well-proportioned, and the law of metal flow which is conform to the actual process was acquired. Through the test check of torque ,it is indicated that the optimization programme is feasible.