The invention relates to a self-adaptive power grid division method suitable for forced oscillation distributed positioning. The power grid topology and the communication topology of an oscillation monitoring system are considered at the same time, and though applying the method to a PDC, the power grid is adaptively divided to a plurality of minimum cut sets, and the minimum cut sets are distributed to corresponding local PDCs for monitoring. Firstly, a node with a PMU is subjected to minimum cut set division and auxiliary control data are obtained; breadth-first search is then carried out onthe remaining grid to acquire the minimum cut set and the corresponding auxiliary control data; after all minimum cut sets and the corresponding auxiliary control data are obtained, a central PDC sends the minimum cut sets and the corresponding auxiliary control data to the corresponding local PDCs for guiding the local PDCs for cooperation; and when the power grid topology or the communication topology changes, the central PDC repeats the above process. According to the method, the oscillation source can be positioned in the minimum cut set obtained through division, the accuracy and the effectiveness of forced oscillation positioning are improved, and important conditions are provided for distributed positioning of forced oscillation.