Abstract: In the context of the energy transition and the goal of "carbon peak and carbon neutrality", it is of great significance to build an integrated energy system with hydrogen energy as the energy conversion medium (H₂-IES) in order to reduce environmental pollution and improve energy efficiency. For the purpose of maximizing the effectiveness of hydrogen in the H₂-IES, a low-carbon operation method of H₂-IES is proposed considering the flexible load of electric-heat and hydrogen energy refined modeling. Firstly, by analyzing the mechanism of hydrogen energy utilization, a refined model of hydrogen energy utilization was established. Secondly, the electric/thermal flexible load model was built, which takes into account the flexible characteristics of the electrical/thermal energy load and the influence of the flexible load on the economic optimization of the system. Finally, considering the costs of outsourcing energy, operation and maintenance, carbon penalty and flexible load scheduling compensation, a low-carbon optimal scheduling model of the H₂-IES was proposed with the goal of minimizing the total operating cost. The calculation results show that, compared with the traditional thin-line modeling and cogeneration energy supply methods, the proposed H₂-IES optimization model and strategy is able to effectively reduce the operation cost and carbon emission, which has higher economy and environmental significance.