The invention discloses a combination method for solving a unit commitment model of an electric power system, relates to the technical field of economic dispatching of the electric power system, and aims to improve the calculation efficiency in solving the unit commitment model. The combination method comprises the steps of establishing the unit commitment model, and simplifying the unit commitment model; regulating a start-stop scheme of the unit commitment model by an outer layer operation module, inputting the adjusted start-stop scheme to an inner layer operation module, solving an economic dispatching module by the inner layer operation module to obtain an optimized target solution; judging whether the optimized target solution satisfies the optimization requirement or not; if not, re-adjusting the start-stop scheme of the unit commitment model by the outer layer operation module, and re-solving the economic dispatching module by the inner layer operation module; and if so, outputting the optimized target solution and the adjusted start-stop scheme, and completing the solving of the unit commitment model. The combination method for solving the unit commitment model of the electric power system is used for formulating the start-stop scheme and an output scheme of a generator unit.