The automatic cable fault location and circulating current monitoring system implements online monitoring for ultra-high voltage cable lines with voltage levels of 110kV and above to realize automatic location of ultra-high voltage cable faults. In addition, the system monitors the circulating current value of the metal shielding layer of the cable in real time, can draw the cable circulating current curve, and alarm the abnormal circulating current cable to realize the online monitoring of the cable sheath insulation. The positioning accuracy of the system is not affected by factors such as line fault location, fault type, line length, grounding resistance, etc. The monitoring data is reported to the host computer through optical fiber communication, and the location of the fault point is determined by the host computer analysis software, which shortens the user's fault diagnosis time and Time to restore line power