Abstract: For the starting procedure of sensorless of coal mine brushless DC motor, the start-up technology based on variable-frequency and increase-voltage method is proposed. On the basis of analyzing mathematical model of coal-mine brushless DC motor and start-up theory of sensorless, the hardware circuit and software program of start-up procedure for coal-mine brushless DC motor sensorless control system is designed. The system can achieve the reliable start-up of coal-mine brushless DC motor, and has the advantages such as simple structure and good stability.