Abstract: The integrated energy system can coordinate the planning of multiple energy sources, improve the absorptive capacity of renewable energy, so as to realize the low-carbon and efficient operation of the system. Based on this, this thesis proposes a comprehensive energy system integrating photovoltaic power generation system, heat storage water tank and internal combustion engine. Considering the constraints of energy balance in three forms of cold, heat and electricity, the genetic algorithm is used to establish the optimization model of comprehensive energy system planning with the minimum annual total cost as the optimization goal, and the annual total carbon emissions and annual total primary energy consumption as the evaluation indicators. The results show that the annual total cost saving rate, annual carbon dioxide emission reduction rate and annual primary energy saving rate of the proposed integrated energy system are 30.67%, 33.26% and 8.93% respectively, compared with the separated production system. In addition, the photovoltaic power generation system in the integrated energy system bears 14.58% of the annual user electric load, effectively improving the economy and energy efficiency of the system.