Abstract: Modeling and simulation abstract real systems and their physical properties into the appropriate mathematical forms and use mathematical methods to solve and simulate the behaviors or performances of the real system. Establishing appropriate mathematical models for the physical processes of the integrated energy system（IES） in various time scales and conducting simulation verification are the basis for analyzing the system operation rules, optimizing operation strategies, and assessing operation performance. Focusing on the modeling and simulation of electricity-gas-heat IESs, this paper first introduces the mechanism models of the electricity, gas, and heating subsystems and coupling units. The research progress and technical difficulties of modeling are then summarized. Furthermore, the research progress of simulation techniques for IESs is described from three key aspects: simulation framework, simulation algorithms, and simulation improvement strategies. In particular, the principle, application status and difficulties of numerical method, semi-analytical method and analytical method in simulation algorithms are summarized. Finally, based on the existing technical difficulties, future research is prospected from two aspects:modeling and simulation algorithms.