In the weak current network environment, due to the grid equivalent impedance, the coupling degree between inverters is enhanced when multiple inverters operate in parallel, resulting in resonance, and the whole system is difficult to be operated in a steady state. An overall resonance suppression strategy is proposed based on the notch filter introducing virtual equivalent admittance to the common coupling point. Firstly, the closed-loop output equivalent impedance model of a single inverter is established. Based on this model, the resonance characteristics of multi machine parallel system are analyzed by Thevenin equivalent. Secondly, the closed-loop Norton equivalent model of parallel operation of multiple inverters is constructed, and the Nyquist criterion for judging the stability of parallel operation of multiple inverters is derived. Then, the obtained Nyquist criterion is used to judge the correctness of the proposed overall resonance suppression strategy. Finally, the effectiveness of the proposed resonance suppression strategy for parallel operation of multi grid connected inverters is verified by simulation and experiments.