Abstract: The paper put forward a control scheme of brushless DC motor with sensor-less.The scheme uses back-EMF integration method to obtain the signal of rotor position,compensates phase shift of the back-EMF detecting citcuit under different speed,and realizes synchronous starting in open-loop of brushless DC motor through increasing frequency and increasing voltage method,so as to realize the control of sensor-less of brushless DC motor.The experiment results showed that the scheme is correct.