Aiming to reduce the torsional vibration of range-extended hybrid system, a powertrain domain control unit based on a multi-core microcontroller was developed. The softwares and hardwares of vehicle control, APU system control, engine control and motor control were integrated. Based on multi-core tasking and inter-core coordination, the synchronization algorithm between the motor phase and engine phase was used, the rectangular torque wave was used for torque compensation, and the active damping control was realized. The experimental results show that the engine speed fluctuation range can reduce by 79.7% under constant speed motoring conditions by using this controller. When the resonance of motoring starting conditions and free stop conditions happens, the amplitude of first-order frequency decreases by approximately 42.9%.