Abstract: When the mine long-distance belt conveyor adopts multi-point driving mode, the multi-motor synchronous control is adopted between the driving points at a long distance. Moreover, the multi-motor synchronous control strategy based on the traditional relative coupling control can not meet the synchronous requirements in the starting process when the rotational inertia of each motor is different, and the synchronous precision is not high when the steady state is disturbed. In order to solve the above problems, an improved relative coupling control method is proposed. A simple structured and easily implemented torque compensator is added on the basis of the traditional relative coupling control, the deviation between the actual rotating speed of each motor and the average rotating speed of all the motors is sent to a proportional controller for adjustment, and then the output result of the proportional controller is taken as a required torque compensation signal. In order to ensure the safe operation of the multi-motor drive system, the output torque of each motor after compensation is subjected to the same amplitude limiting. The simulation and experimental results show that the improved relative coupling control with torque compensator can realize the speed synchronization of multi-motors in the starting phase under different moments of inertia without affecting the dynamic response speed of the system. The proposed method ensures the system to have good anti-disturbance performance in steady state operation and high synchronization precision after disturbance.