The invention discloses a power distribution fault monitoring system which comprises at least one wireless power distribution monitoring sensor, a concentrator and a monitoring master station. The at least one wireless power distribution monitoring sensor is connected with a power distribution transformer through an optical fiber, and is used for collecting the fault information of the power distribution transformer. The concentrator is connected with each wireless power distribution monitoring sensor through a wireless sensor network, and is used for receiving the fault information collected by each wireless power distribution monitoring sensor. The monitoring master station is connected with the concentrator through a wireless optical network, and is used for receiving the fault information received by the concentrator. The characteristics of the optical fiber, a WSN network, a power line and a passive optical network are comprehensively used, the problems that wiring is difficult, the rerouting project amount is large, the line can be damaged easily, moving can not be achieved, operating is unstable, and the reliability is poor in an existing power distribution fault monitoring network are effectively solved, and the power distribution fault monitoring system is suitable for power distribution fault monitoring.