ABSTRACTThe integrated energy system (IES) comes out with significant advantages in reducing carbon emissions and improving energy efficiency. However, the complicated electrothermal couplings in the IES operations pose significant challenges to dynamic process simulation. To inquire into the dynamic electrothermal coupling characteristics, a bidirectional coupling multi‐rate real‐time simulation method for the thermal‐electric systems (TESs) based on the functional mechanism is proposed to depict the dynamic interaction process between the subsystems. The stability of the multi‐rate simulation method is proved by small signal analysis. Then, a real‐time dynamic simulation platform for the TESs is developed, which is utilized to verify the effectiveness of the proposed method in thermal power tracking and electrical power tracking modes. The simulation results validate that the proposed multi‐rate simulation method for the TESs in this paper can effectively reflect the dynamic process and enhance the simulation efficiency.