The invention relates to a method for indicating a fault in a power circuit and an indicator thereof, belonging to the power circuit detecting equipment technical field. The method comprises the following steps that: in a hardware environment comprising a short circuit detection loop, a central core-logic processing unit and an alarming indicator, the central core-logic processing unit receives detection signals, immediately compares the peak electrical parameter with corresponding preset value, compares the input peak electrical parameters sequentially within a preset time interval and finally determines to give an alarming signal to the alarming indicator. The central core-logic processing unit compares the adjacent peak values of the fault current as well as the signal frequency and gives an alarming signal only when a fault is detected according to the facts that the peak values are almost equal and that the frequency is consistent with the voltage frequency of the system; otherwise, if the result comes out as the adjacent values decreases gradually, an impulse current due to inverse power supply is detected and the invention does not give an alarming signal, thereby effectively avoids the misoperation of the alarming indicator.