Electricity-gas-heat integrated energy system as the future development and application of the main energy supply methods and systems, not only through the coordinated scheduling to meet the different types of energy loads of energy demand, but also covers such as wind power, photovoltaic and other clean energy as well as energy storage equipment, such as a variety of distributed energy supply, to improve the energy utilization rate is more efficient at the same time to achieve a more environmentally friendly results. In this paper, based on the integrated energy system modeling and trend calculation method, for the characteristics of the gas grid and heat grid, the grid uses the Newtonian inverse push method for trend calculation; for the gas grid, the Newtonian inverse push method is used; for the heat grid, the linear Newtonian method is used. It mainly focuses on system safety and economy, determines the system safety index system, and conducts research on static safety analysis and optimal operation calculation.