According to the characteristics of cable arrangement environment and application requirements, a new design method for an early alert system of all-fiber power cable fault location is introduced. The fiber combined with power cable is used as sensors in the system. Electric leakage fault from power cable is monitored and located in real time by collecting and analyzing the vibration waveforms around power cable. Experimental results show that the vibration around power cable along fiber line can be monitored effectively by the system. And measuring distance is more than 20 km and locating accuracy is ±3 m.