The high-power electromechanical transmission(EMT) system is a typical dual-mode hybrid power transmission system. The torque fluctuation of internal combustion engine causes serious shock and vibration problems of EMT. It is an important way to improve the life and smoothness of EMT system by using high dynamic regulation of motor torque to suppress the torsional resonance amplitude. Firstly, a lumped parameter rotational dynamic model of multi degree of freedom EMT system is established, and the inherent torsional vibration characteristics and dynamic coupling mechanism of the system are analyzed. Secondly, based on the synchronous response of the two motors in the open-loop state, a master-slave coupling EMT torsional active control strategy is proposed, and a speed feedback proportional differential control algorithm is designed. Then, the influence of control parameters, including lever coefficient Kab, proportional coefficient Kp and differential coefficient Kd, on the vibration characteristics of the system is analyzed. Finally, the calculation is carried out in the frequency domain and compared with the optimal modal control algorithm. The results show that the lever coefficient Kab and differential coefficient Kd of master-slave control can change the natural frequency of torsional vibration of the system, thus significantly changing the vibration response of the system. Selecting appropriate control parameters can achieve peak clipping of EMT torsional resonance amplitude, which is also of great significance to improve the NVH performance of the system.