Abstract: In view of problem of low location precision in fault location method of underground power cable based on traditional wavelet transform caused by asymmetry of wavelet function, the paper proposed a fault location method of underground power cable based on GHM multi-wavelet. It analyzed principle of multi-wavelet theory, and introduced application of the GHM multi-wavelet in fault location of underground power cable. The simulation result shows that singular points of each scale cannot occur migration after signal of fault current of power cable is transformed by the GHM multi-wavelet, which improves precision of fault location.