The invention discloses a wide-area-distributed city/county scheduling and monitoring integrated system subarea disconnection/connection operation method. The method is specifically characterized by, to begin with, establishing a backbone network dual-network structure which has spanning tree characteristics and is suitable for wide-area-distributed city/county scheduling and monitoring integrated operation and supports disconnection/connection operation; with the above network architecture, network communication can still remain normal when no more than three faults occurs in a backbone network; when four faults occurs in the backbone network, a subarea network state recognition module triggers county scheduling to go into a disconnection state, thereby enabling multiple islands to finish monitor tasks independently and separately and guaranteeing city scheduling to be able to receive data of factories and stations governed by the county scheduling; and after one or multiple links in network links of the disconnection county scheduling return to normal, the subarea network state recognition module triggers the county scheduling to go into a subarea connection state, thereby enabling the county scheduling to go back to the integrated operation state again. The method helps to solve the problem of network reliability for city/county integrated wide-area operation, and provide guarantee for safe and stable operation of city/county smart power grid dispatching technology support system.