The resonance of grid － connected multi － inverter system is the result of the joint action of filter output harmonic and grid harmonic． The resonance of LCL filter is one of the main factors of harmonic output of filter． Therefore，the influence of the resonance damping method of LCL filter on the resonance of grid － connected multi － inverter system is analyzed． Firstly，the mechanism of harmonic interaction in grid － connected multi － inverter system is analyzed． Secondly，the impedance model of grid － connected multi － inverter system with passive damping and active damping is established． Then，the influence of two damping methods on low frequency resonance and supraharmonic resonance is compared and analyzed． Finally，3 grid － connected inverters are used for simulation experiment to verify the effectiveness of the above － mentioned theory．