Abstract: To improve the absorptive ability of new energy and realize low-carbon and economic operation of integrated energy system, a combined gas, heat and power (abbr. CGHP) system model and coordinated operation strategy of the source-load sides considering the substitution of energy on the load-side was considered. Firstly, according to the operating characteristics of power to gas (abbr. P2G) and carbon capture system, a basic frame of CGHP system model was built to research and analyze the thermoelectric operation characteristic of CGHP system and the quantitative relation of electricity-gas-heat. Secondly, according to the source-side energy price information, an comprehensive demand response model for the substitution and transformation among loads under the carbon trading mechanism was established. Finally, under the premise of ensuring the satisfaction with users’ energy consumption, taking the minimized daily operating cost of integrated energy system as the objective, a dispatching plan at the source-load side of the grid was reasonably arranged. The results of the computing example show that the proposed model and operation strategy are feasible and effective, and can provide some references for promoting the integrated energy system to absorb new energy, decreasing the emission of CO2 and reducing daily operating cost of the system.