This paper proposes a new solution to locate the open circuit fault of the switching device IGBT and diode in STATCOM. It’s analyzed that part of the current waveform will change or miss, when the single IGBT and diode open circuit fault occur. So it can be concluded that the reactive power corresponding to the positive and negative current of one phase will reduce, when IGBT and diode open circuit fault occur in this phase. Sl^m, the normalized value of reactive power corresponding to the positive and negative current of each phase is used to locate the fault phase. Besides, dlx, 1/4 cycle power difference of the fault phase current, is utilized to help differ the IGBT fault from the diode fault. Simulation proves that it not only can differ the single IGBT fault from the single diode fault, but also can be adopted in part of the situation where two IGBTs fault or two diodes fault occur. Besides, it is load independent except in the light load condition.