The nonlinear dynamic characteristics of metal rubber isolator are studied and a dynamic model with parameters with physical meaning is developed in this paper. According to the experimental results from a setup with single degree of freedom, the identification method for related parameters is researched. The nonlinear function that describes the dynamic behavior of the system is converted to the series of linear functions by using energy method and least square method. The identification results show good agreement with the experimental results and explain the effect of parameters on the performance of isolators.