The integrated energy system (IES) is developing rapidly. Under the background of “dual carbon” strategy, reducing carbon emission has become a research focus. In this paper, a day-ahead optimal scheduling of IES is presented with comprehensive considering of carbon emission target, constraints and demand response (DR). Firstly, the architecture and strategy of IES based on carbon information flow are analyzed. Secondly, an integrated DR model including electricity, gas, heat and cooling is established by using the transfer and substitution characteristics of demand-side load, considering multi-energy complementarity. Finally, with the objective of minimizing economic cost and carbon emissions, a day-ahead optimal scheduling model of IES considering carbon emission target, constraints and DR is established by adding carbon emission constraints to the existing scheduling constraints. Simulation results show that the method can effectively reduce the economic cost and carbon emissions of the system, improve load distribution in time, and provide an effective means for low-carbon power grid scheduling.