Abstract: In order to improve the power utilization rate of integrated energy system,further limit carbon emissions and realize lowcarbon economic operation,an optimal scheduling model of integrated energy system is proposed based on demand side response and tiered carbon trading mechanism. Firstly,considering the flexible response ability of multiple loads on demand side,a demand response model with electricity-gas-heat load is constructed. Secondly,the life cycle assessment method is used to analyze the carbon trajectories of different energy chains in integrated energy system and accurately calculate the total carbon emission of the system.Finally,the tiered carbon trading mechanism based on life cycle assessment is introduced into the integrated energy system,the optimal scheduling model is constructed aiming at minimizing the energy purchase cost,carbon trading cost and wind abandonment cost.Then,CPLEX toolbox is invoked to optimize the total cost under the four typical scenarios. The results show that under the tiered carbon trading mechanism,the total cost is reduced by 2.58% and the carbon emission is reduced by 15.71% with the introduction of demand response,which greatly reduces the carbon emission while improving the operation economy of the system.