According to the actual electrical parameters of the change rate at high and low temperature current amplification factor of power transistor, the simulation software of the TCAD semiconductor device and the transistor principle were analyzed depth. The results show that, for the power transistors with large test current and high current amplification factor, the change rate at high and low temperature current amplification factor of can be effectively improved by decreasing the doping concentration in the emitter region and increasing the doping concentration in the base to a certain extent. At a certain concentration of the surface of the emitter region and the surface concentration of the base, the optimization of the junction depth and the width of the base can meet the requirements of the current amplification index at room temperature. Combined with the simulation results, the key processes were solved through the actual flow sheet. The flow sheet results show that the process method of reducing the doping concentration in the emitter region and increasing the doping concentration in the base can effectively improve the change rate of current amplification factor at high and low temperature, and control the measured values of other parameters to meet the design requirements.