The influence of renewable energy access is seldom considered in the current analysis of low frequency oscillation of power system, and the mechanism of the power electronic converter on low frequency oscillation of power system is not clear. In this paper, a low-frequency oscillation analysis model of renewable energy access system is established, the analytical expression of damping torque of the system is derived by damping torque analysis (DTA), the influence of converter control parameters, grid-connected position, and renewable energy input power ratio on the low-frequency oscillation of the power system is quantitatively evaluated, and the law of the control parameters and operating conditions of the converter on the damping improvement of the power system is obtained, and the correctness of the proposed method is verified by MATLAB/Simulink simulation.