The invention provides a capacity subsidy calculation method and device for a compressed air energy storage system. The method comprises steps that a first target function is constructed through taking the maximum revenue of a compressed air energy storage power station as a first optimization goal, and operation constraints of the compressed air energy storage power station are determined according to energy storage operation characteristics; a second target function is constructed through taking the maximum revenue of a power grid as a second optimization goal, and power grid side constraints are determined according to operation characteristics of a conventional unit and a wind turbine generator; based on the first target function, the operation constraints of the compressed air energystorage power station, the second target function and the power grid side constraints, taking the compressed air energy storage power station as a lower-level main body and the power grid as an upper-level main body, a two-level game model is constructed; the two-level game model is transformed into a single-level model for solution through utilizing the KKT condition method, and the optimal capacity subsidy of a compressed air energy storage system is obtained. The method is advantaged in that the theoretical basis can be provided for power grid enterprises to develop capacity subsidy strategies.