The invention belongs to the technical field of fault diagnosis of power distribution networks, and particularly relates to a power distribution network fault diagnosis system based on MAS optimization coordination. The system comprises a diagnosis Agent, an optimization coordination Agent, a data processing Agent, a data acquisition Agent, a communication Agent and a user interface Agent. The diagnosis Agent comprises a global diagnosis Agent and an area diagnosis Agent. The optimization coordination Agent comprises a global optimization coordination Agent and an area optimization coordination Agent. The area diagnosis Agent comprises a switch layer diagnosis Agent, a feeder line layer diagnostic Agent and a transformer substation layer diagnosis Agent. A power grid locally obtains a preliminary diagnosis result through area diagnosis, global diagnosis and a global diagnosis result are used for forming a global diagnosis conclusion, coordination between area diagnosis and between areadiagnosis and global diagnosis is coordinated and controlled, the diagnosis strength and accuracy are enhanced, and the diagnosis precision is guaranteed.