Abstract: In order to solve the problem that the carbon emission calculation of combined heat and power（CHP）units in existing research does not conform to the actual physical characteristics,a low-carbon dispatch optimization of integrated energy system（IES）based on CHP carbon emission analysis is proposed. Starting from the internal structure of CHP unit,the energy transfer process among various parts inside the CHP unit is analyzed,the CHP unit power and carbon emission flow diagram are drawn,the power balance equation of each part is written down,the equivalent thermal power of the exhaust gas emitted by CHP unit is obtained. Considering the relationship between the carbon emission and the exhaust gas emission rate,combined with the thermodynamic equation of exhaust gas emission,the relationship among the exhaust gas emission rate of CHP unit,the input air flow and output power is obtained. An IES low-carbon dispatch optimization model based on CHP unit carbon emission analysis is proposed to solve the IES low-carbon scheduling optimization results with the minimum total operating cost as the goal. The optimal scheduling results under different CHP unit operation modes are analyzed by an example,and compared with the existing methods,the effectiveness of the proposed model in reducing carbon emissions is verified.