The invention discloses a distribution network failure moment determining method based on multi-order wavelet function transformation. The method is capable of adapting to multiple failure types and multiple failure locations and accurately positioning the failure moment. The method disclosed by the invention comprises the following steps: adopting FFT (Fast Fourier Transform) of a moving time window according to a general format (COMTRADE) waveform file exchanged by transient data of a power system collected by a failure indicator, judging aiming at the calculated distortion factor, and generally locating the failure moment, so as to save time for subsequent wavelet processing; and accurately locating failure points by adopting a method for performing wavelet transform by adopting a multi-order wavelet function. According to the method, characteristics of wavelet functions of different orders are utilized, the stability and accuracy of failure moment determination are taken into account, the effectiveness of the method is validated by analyzing various different actual failure waveforms, and reliable method supports are provided for detection of the failure indicator device.