Abstract: In order to reduce the vibration of the internal combustion engine in ships,the internal combustion engine and its auxiliary equipment are installed in multi-stage vibration isolation system. The modeling of the multistage vibration isolation system is carried out by moving frame method（MFM）,which is adapt to describe the various motions of the vibration foundation and simplify the complexity of the dynamic equation. Aiming at the complex vibration isolation system with multiple supports,the force level difference is defined based on the transfer force,which is used for evaluating the isolation performance of the vibration isolation system in the theoretical calculation and designing. The influences of ship motions on the performance of vibration isolation system are studied.The results show that the isolation performance of the vibration isolation system is significantly affected by the motion state of the ship. With the increasing of the amplitude or frequency of the ship vibration motion,the vibration isolation efficiency of the vibration isolation system will become worse. The influence of ship rolling or pitching on the vibration isolation performance is more complex than that of heaving.