In view of the problems of less interaction between source-load entities,high carbon emission intensity,low wind-solar power consumption capacity,and poor overall operating efficiency of the regional integrated energy system (RIES),an optimization method is proposed for the economic low-carbon operation of the RIES taking into account the demand response of electricity-gas-thermal prices. Based on the common commodity attributes of electricity,natural gas,and thermal energy and the dispatchable value of multiple flexible loads,a price-demand response model of electric-gas-thermal is established,which effectively enhances the incentive effect of price signals on load participation in demand response. To fully tap into the low-carbon potential of the system,stepped carbon trading is introduced to improve the actual carbon emission model. With the minimum system operation cost as the optimization goal,the influence of different operation modes on the economy and low carbon of the system is studied. The case study results show that the operation optimization model of price demand response and stepped carbon trading can achieve economic low-carbon system operation and wind-solar power consumption capacity while achieving peak-shaving and valley-filling.