The solution and analysis of a collision vibration system with variable mass were focused and the influence of vibration mass varying with time on the dynamic behaviors of the collision vibration system was discussed.The asymptotic method was used to solve the vibration equations with variable mass,and the method of Runge Kutta was used for numerical calculation.The results show that the responses calculated by the analytical method and the numerical method are in consistency and the asymptotic method is effective for the solution of the dynamic behaviors of nonlinear systems.The calculation also shows that variable mass will make the system response produce a certain mutation.The variation coefficient and the changing frequency of vibration mass will affect the mutation's period and the amplitude of system respectively.When the variation coefficient is zero,the system response is stationary.The greater the variation coefficient is,the greater the mutation is.The greater the ratio of vibration frequency to mass varying frequency is,the longer the cycle of response mutation is.