The impedance interaction between the inverter and the grid cannot be avoided. When the distributed capacitance of the transmission cable is large and cannot be ignored, multiple resonance points will appear in the grid?connected system of the inverter, which is easy to cause high?frequency resonance. From the perspective of impedance interaction, this paper uses passivity theory to analyze the potential unstable region of grid?connected inverter system, and the influence of line length and grid side impedance on the resonant frequency of grid?connected inverter system. Aiming at the problem of high frequency resonance of the system, the active damping method of series second?order low?pass filter and phase compensator in the inverter control path is proposed to reshape the impedance of the inverter, so that the output impedance of the inverter can meet the passive condition in the whole frequency band, achieve the purpose of suppressing high frequency resonance and improve the stability of the system. Finally, the simulation model in Matlab/Simulink is established, verifying the effectiveness of the proposed scheme.