With the implementation of the national "dual-carbon" policy, the demand for zero-carbon emission of integrated energy systems in low-carbon parks has become increasingly urgent. In order to improve the utilization rate of renewable energy, the efficiency of multi-energy coupling utilization and the degree of decarbonization in low-carbon parks, a comprehensive energy system optimization scheduling model for low-carbon parks is proposed by considering the carbon capture, utilization and storage (CCUS)-hydrogen energy comprehensive utilization (HECU) system optimization and dispatching model. Firstly, hydrogen storage was added to the traditional electricity-to-gas conversion, while the waste heat generated by the operation of hydrogen fuel cells (HFC) and methane reactors was reused to realize electricity-heat-gas co-generation, thus promoting the modularization of HECU and the gradient utilization of energy. Secondly, CCUS technology was introduced and combined with HECU to sequester the captured CO₂ and synthesize methane to establish a comprehensive CCUS-HECU operation framework. Finally, considering the participation of electric/thermal flexible loads in the demand response of the integrated energy system, and adding the stranded and additional costs reduced by equipment after low-carbon retrofit into the cost calculation, the optimal scheduling model of the integrated energy system of the low-carbon park with the goal of minimizing the total cost was established and solved by using the CPLEX solver. The example results show that the proposed model can effectively reduce the comprehensive operating costs and carbon emissions of the system, improve the utilization rate of renewable energy, and realize the economic and low-carbon operation of the system.