Abstract: The green hydrogen energy achieves a zero-carbon emission in the source by utilized clean energy surplus power to produce hydrogen by water electrolysis, which plans a vital role in global energy transition. Aiming at the problems of imperfect market mechanism of green hydrogen energy certificate, this paper proposes an optimal operation method of integrated energy system considering green hydrogen energy certificate combination double auction and hydrogen production by hydropower. Firstly, aiming at the problem of unbalanced price and quantity matching of green hydrogen certificate in the park, a bidding model of combinatorial double auction (CDA) trading mechanism is proposed. Secondly, an integrated energy system optimization model with hydrogen production by hydropower is established, and the green hydrogen certificate combination double auction mechanism is introduced. Finally, the simulation analysis is carried out by taking the integrated energy system containing hydropower and hydrogen production in a province as an example. The results show that the proposed model not only effectively improves the operation economy of the integrated energy system (IES), but also improves the consumption of renewable energy in the system.