Abstract: The impedance distribution of PV plant sink network is complex, and the mechanism of high frequency resonance caused by the interaction with Static Var Generator (SVG) and grid impedance is unknown, and there is a lack of effective high frequency resonance suppression measures. The paper focuses on the mechanism of high-frequency resonance and its oscillation suppression measures in photovoltaic power plants with static reactive power devices. Firstly, a unified impedance model of PV power plant is established, the high-frequency influencing factors of the impedance of each device in PV power plant are analyzed, and a high-frequency characteristic impedance model is established. The paper proposes a resonance suppression method of PV plant based on SVG high-frequency impedance reshaping, and achieves effective suppression of high-frequency oscillation of PV plant through SVG high-frequency phase angle compensation, and gives the parameter adjustment method; finally, the analysis of high-frequency oscillation mechanism and its experimental verification of suppression control are completed by using RT-LAB control hardware in the loop.