The invention provides a rapid cable temperature calculation method based on parameter fitting.The method includes the steps that firstly, according to cable laying characteristics, a heat circuit method is adopted, a transient cable temperature heat circuit model for parameter fitting is established, and a cable temperature differential equation is listed and written; aiming at a certain specific working condition of a cable, the cable gets into a zero initial state, rated currents are applied to the cable, and the cable core and surface temperatures of the cable generated when the cable temperature reaches a stable state are measured; according to the actually-measured cable core and surface temperatures of the cable, heat capacity and heat resistance heat parameters in the cable differential equation are fit through a trust region algorithm; finally according to the fit heat parameters, a cable temperature transient heat circuit is solved, the cable temperature is obtained, and a calculation equation is simplified.According to the rapid cable temperature calculation method based on parameter fitting, transient heat parameters of a conversion model can be rapidly acquired in combination with the actually-measured temperatures under the rated transmission capacity of the cable, the simplified calculation equation of the cable core and surface temperatures of the cable is obtained, and the purpose of rapidly calculating the cable temperature is achieved.