Abstract: With the increase of distributed PV penetration, the existing three-staged overcurrent protection faces the risk of malfunction. This paper presents a new fault direction identification based on the distortion characteristics of fault current waveforms. Firstly, the difference is explored between the fault current waveforms supplied by the distributed PV and by the traditional synchronous power. The characteristics of PV fault current distortion and the generation mechanism of harmonic components are studied. Secondly, the method of fault feature extraction is studied, and the direction blocking criterion based on fault current waveform distortion is proposed. The simulation results validate that the proposed method is able to reliably decide the forward and the reverse fault directions under different inverter control strategies with the abilities to withstand the fault resistance and the noise of signal sampling. This idea converts the interference of nonlinear characteristics to the fault direction criteria with no voltage measurement information and communication equipment, which will effectively reduce the technical difficulty of the distribution system construction.