The invention discloses an outage analyzing and warning system for power distribution networks. The outage analyzing and warning system comprises an information collecting and analyzing system, an overvoltage warning system and a power distribution network monitoring system. The information collecting and analyzing system, the overvoltage warning system and the power distribution network monitoring system are connected with one another in parallel, the information collecting and analyzing system comprises a power grid dispatching OMS (outage management system), a dispatching automation system, a power utilization information acquisition system, a data analyzing system, a threshold judging host and an alarm device, the overvoltage warning system comprises a special voltage detection voltage divider, an overvoltage data acquisition system and an overvoltage detection server, and the power distribution network monitoring system comprises a monitoring terminal and a monitoring server. The outage analyzing and warning system has the advantages that overvoltage of the power distribution networks can be measured by the outage analyzing and warning system for the power distribution networks in real time, accordingly, faults of the power distribution networks can be analyzed, and influence of external factors on the power distribution networks can be monitored and warned.