The invention provides a combined system model of aggregation temperature control loads and generator excitation and a backstepping coordinative control method thereof. The method includes steps: firstly constructing a single infinite bus system structure containing temperature control loads (TCLs), and deducing and constructing a combined system mathematical model of the aggregation TCLs and generator excitation based on a double-linear aggregation model of the TCLs; and then designing a multi-index coordinative control strategy of the aggregation TCLs and generator excitation by employing abackstepping control principle, and proving the stability and the validity of a controller from theory and simulation. Compared with other models and control methods, the model and the method are novel in that a coordinative control system is established with the combination of the aggregation TCLs and generator excitation, the multi-index nonlinear coordinative controller with good performance isdesigned, and the TCLs can produce a bigger effect in regulation and control of an electric power system.