Abstract: dominant power system results in long-term and short-term coordinated scheduling challenges. Therefore, an optimal scheduling model of an electricity-gas-hydrogen hybrid integrated energy system considering seasonal hydrogen storage is proposed based on electricity-gas-hydrogen coupling. First, typical scenarios in high- and low-energy seasons are obtained based on time series decomposition and scene clustering method. Then, the operation model of the electricity-gas-hydrogen hybrid integrated energy system is developed based on the DC power flow model of the power system, and the quasi-dynamic natural-gas flow model considers green hydrogen injections. Moreover, sequential second-order cone programming is proposed to efficiently deal with nonlinear constraints in the gas flow model. Finally, numerical results verify the proposed model's economy and the solution method's feasibility. The multi-energy coupling relationship between electricity, gas, and hydrogen under seasonal hydrogen storage is also analyzed. Simulation results show that the operating cost of the proposed model is reduced by 6.43% compared with that obtained from traditional electricity-gas systems.