In order to improve the output-voltage performance and fast response of inverter power supply control system, this paper presented a neural network fractional order controller. Based on introducing the model of three- phase inverter and fractional order controller, this paper used the improved BP algorithm to adjust parameters of fractional order controller. The simulation indicated that the improved one which was designed in this paper is better than the traditional one in the field of fast response and output voltage, and the experiment made further efforts to prove effectiveness of the controller.