The improved active anti islanding protection will affect the quality and the improved passive anti islanding protection is too complex, this paper proposed combining the main passive anti islanding protection method of network current based on the detailed analysis of islanding detection principle, namely the passive anti islanding operation control plays a major role, when it failure the active anti islanding control play a protective role. The main process is as follows: firstly, the voltage and frequency of the common coupling point is detected, and if the protection threshold is exceeded, the inverter is disconnected, if it does not go beyond then using the based on the common connection point of the positive feedback voltage applications the detection method and the traditional frequency-based positive feedback frequency shift method to make a simulation contrast, primarily to illustrate that the proposed method compared to the traditional positive feedback frequency based on the frequency shift method is not inserted in the dead zone in the output current waveform, the simulation results not only validate the method of power quality is relatively less affected by the current network, and can effectively prevent the occurrence island effect.