The differences in inertia effects on multiple energy sources cause an imbalance between energy supply and load demand. Therefore, an operation optimization method for a comprehensive energy system with electric and thermal coupling characteristics is proposed. This method adopts the thermal system to reduce the system operation cost and improve operational reliability. Firstly, the method takes the energy transmission network of IES as the basis and establishes the model of the heating pipeline. Secondly, the method also takes the lowest total operating cost of the system as the goal, combines the power balance and equipment operation safety and other constraints, considers the electro-thermal coupling characteristics, establishes the corresponding IES operation optimization model, and applies the genetic algorithm to solve it. Finally, the simulation results show that the method can effectively reduce the system operation cost while ensuring the smooth and safe operation of the equipment based on the optimization model.