The invention relates to an optimal scheduling method for an electric power system. The method comprises the following steps that: obtaining the wind power output prediction error of the electric power system; on the basis of a Monte Carlo simulation algorithm, generating a plurality of wind power output scenes corresponding to the wind power output prediction error; on the basis of a K mean valueclustering algorithm and a preset target scene number, classifying the plurality of wind power output scenes to obtain the target scene of the preset target scene number; and on the basis of the target scene, optimizing output which contains a heat storage optothermal power station and a thermal power plant unit, and enabling the total scheduling cost of the electric power system to be minimum. By use of the method, firstly, according to the wind power output prediction error, the Monte Carlo simulation method is adopted to generate a certain quantity of scenes, then, the K mean value algorithm is adopted to reduce the scene into the target scene number, and then, minimum total scheduling cost is taken as a target on the basis of the target scene to optimize the output of the optothermalpower station and the thermal power plant unit in a scheduling process. The method is convenient for analyzing the influence of the optothermal power station and wind-electricity combined operation onthe integral operation of the electric power system. The method is simple and is convenient in engineering application.