Brushless DC motor has the operating characteristics of DC motors, and also has the advantages of brushless AC motor. It has the advantages of small size and light weight, so they are widely used in various industrial applications. In this paper, for brushless DC motor simulation, it introduces its working principle and mathematical model, using the six-step inverter to ensure the normal operation of the motor ,with closed-loop speed structure to ensure steady-state and dynamic performance, enhanced its reliability.