The invention provides a method of evaluating the comprehensive stability margin of a combined thermoelectric system, which relates to the technical field of thermoelectric system stability evaluation. Through acquiring the coupling degree of the combined thermoelectric system, the heat storage efficiency, the peak regulation ability of a thermoelectric unit and the consumption and wind curtailment ability, influences of the above four factors on the stability margin of the combined thermoelectric system are calculated through corresponding formulas, the occupied weight of each factor is obtained, and finally, through integration, the stability margin level of the combined system is obtained. The stability is evaluated in the level of the combined thermoelectric system, advantages of physical properties of an electric system and a thermal system can be made full use of, and the optimal configuration capability of the energy system in a large space-time range is improved.