The present invention discloses an optimization method for solving an economic dispatching model of a multi-area power grid, and relates to the technical field of power system economic dispatching, inorder to cope with the randomness and volatility of new energy electric fields, and at the same time realize data privacy protection and independence of regional scheduling optimization in the multi-area power grid optimization dispatching. The optimization method comprises: decoupling a multi-area power grid into a plurality of sub-area sub-networks, independently sampling a new energy electricfield output power scene from each sub-area sub-network, and establishing a multi-area power grid random dynamic economic dispatching model; decomposing the dispatching problem of the economic dispatch model into the forecasting scenario dispatching problem and the error scenario dispatching problem of each sub-area sub-network; and solving the forecasting scenario dispatching problem and the error scenario dispatching problem of each sub-area sub-network one by one, and obtaining the convergence of each sub-area sub-network. The optimization method for solving an economic dispatching model ofa multi-area power grid provided by the present invention is used to independently formulate a dispatching scheme for sub-area sub-network.