Abstract: The disclosure provides a method and a system for dispatching a multi-region power system. The method includes: obtaining, by each regional system operator, basic operating parameters of the regional power system; establishing, by each regional system operator, a dispatching model of the regional power system based on the basic operating parameters; identifying, by each regional system operator, an aggregation model of the regional power system based on the dispatching model of the regional power system; reporting, by each regional system operator, the aggregation model to the cross-region system operator; establishing, by the cross-region system operator, a reduced dispatching model of the multi-region power system based on the aggregation model from each regional system operator; and solving, by the cross-region system operator, the reduced dispatching model to obtain a dispatching result of each regional power system.