In order to increase the efficiency of energy utilization and improve the operation economy of the integrated energy system, this paper constructs the optimal scheduling model of the electric-gas-hydrogen integrated energy system, including the power sub-network, the natural gas network and the electrical coupling part. Firstly, from the basic structure of the system, the energy conversion relationship between each subsystem is analyzed, and the mathematical model of each subsystem is established. Then, the optimal scheduling model is established to minimize the objective function including the cost of electricity purchase, the cost of gas purchase and the cost of operation and maintenance of each equipment. Finally, the effectiveness of the relevant schemes is tested by using the example of IEEE33-node system and 20-node natural gas system, which shows that the schemes that take into account pressure energy generation and hydrogen blending of natural gas pipeline network have good economy, and improve the absorption capacity of renewable energy in the integrated energy system to a certain extent.