Driven by the "dual carbon" goal, an important role is played by the integration of multiple carbon-emission reduction value warrants in the low-carbon economic transformation of the integrated energy system. To this end, an optimal scheduling strategy for the combined heat and power integrated energy system, based on the joint interaction mechanism of green certificate-carbon trading-China certified emission reduction is proposed. Firstly, the integrated energy system is guided to constrain carbon emissions by considering the joint mechanism of green certificate trading, ladder carbon trading, and national certified voluntary emission reductions. Then, a new cogeneration model with an adjustable heat-to-electricity ratio is proposed so that the flexible resources in the integrated energy system can be fully utilized and the low-carbon and economic performance of the integrated energy system can be further improved. Finally, the rationality and effectiveness of the proposed strategy are verified by setting the comparison scenario and using MATLAB to solve the constructed low-carbon scheduling model of the integrated energy system. Through example analysis and demonstration, it is shown that all methods can promote the low-carbon economic operation of the integrated energy system.