Abstract: To improve the identification speed of single switch open-fault of VIENNA rectifier, through analyzing the characteristics of current in the VIENNA rectifier of single switch open-fault, an identification method based on the angle of current without additional hardware circuits is proposed. By using the angle of input currents and the instantaneous value of non-fault phase currents to locate fault-phase and fault-switch, the method realizes online identification of single switch open-fault in the VIENNA rectifier. Meanwhile, the VIENNA rectifier has strong resistance to load fluctuation and shortens the time of locating fault-switch the same as the time of locating fault-phase. The experimental results show that it can identify the single switch open-fault of VIENNA rectifier on line in 10%~70% power frequency cycle, which guarantees the safe operation and subsequent maintenance of the rectifier.