The invention relates to a complementary method for handling a fault in a distribution network based on dual cable power supply. An analysis is conducted for a dual cable power supply distribution network to obtain a solving strategy for differential fault handling. To ensure, as for dual cable power supply, the dual power supply property of users after non-fault recovery is to avoid failure in fault positioning of a distribution network due to false alarm phenomena of dual cable faults, to shield false alarm signals that cannot be confirmed by expanding the scope of isolation and to include a faulty region in the scope of isolation. The invention considers the adaptability of fault handling functions of the dual cable power supply distribution network at this stage, the impact of the trend for special operating modes on a general fault handling logic algorithm, and the general fault handling logic flaws, and ensures wide adaptability and practicability of fault handling of the distribution network, thereby improving the fault handling reliability of the distribution network, shortening the power supply time and providing customer satisfaction.