Abstract:The dynamic response characteristics of Metal Rubber vibration isolation system was studied by the FFT multi-harmoinc balance method, and the new definition of the nonlinear vibration transmissibility was proposed by introducing the “average power ratio”. Through the analysis of metal rubber nonlinear constitutive relation of vibration isolation system, the response and the vibration transmissibility formula of the system were deduced by using FFT multi-harmonic balance method. Then through the comparisons of the results which calculated by the numerical method, the single harmonic method and the more harmonic method, it shows that the result get by FFT multi-harmonic balance method is much more closer to the numerical solution than the one harmonic balance method. Theory analysis and simulation results show that the FFT multi-harmonic balance method can be used to get the accurate analytical solution of the dynamic response characteristics of the Metal Rubber vibration isolation system, this method will have important application value in engineering.