Based on the high frequency oscillation characteristics of Guangxi Muge wind power plant and the control principle of the grid-side frequency converter of a wind turbine, a transfer function model of the wind turbine grid-side frequency converter is established. By comparative analysis of the transfer function model of the grid-side frequency converter and its Norton equivalent circuit, the frequency domain expression of the grid-side equivalent inverter impedance is obtained. Bode diagram analysis of amplitude-frequency and phase-frequency characteristics of the grid-side frequency converter equivalent impedance show that the incidence of high frequency oscillation is caused by resonance from the grid and converter impedances at a certain frequency. To overcome the problem of high-frequency oscillation, the method of modifying the feedforward voltage coefficient then changing the amplitude and frequency of the equivalent impedance and converter phase-frequency characteristics is proposed. The open-loop transfer function can be obtained by modifying the feedforward voltage coefficient of the grid connected system transfer function. Bode diagram analysis shows that the margin stability of the system is increased significantly after modification. It has been verified that a Muge wind power plant can operate normally under various working conditions after taking this measure. This demonstrates that the proposed solution is effective. This work is supported by the National Natural Science Foundation of China (No. 61803219).