The integrated energy system of buildings（BIES）has a large load capacity and various types of energy. How to coordinate the operation of different types of energy sources and loads to realize the peak shaving and valley filling of the power grid is a research hotspot.Considering the factors such as light storage and soft environment comfort, BIES is optimized. First, a photovoltaic（PV）output model based on the uncertainty of solar radiation intensity distribution is constructed by using the Beta distribution method; second, considering the mobility characteristics, an electric vehicle（EV）storage model is proposed and a quantitative model of building environmental comfort that takes into account the influence of temperature on flexible loads are constructed; finally, based on the mixed-integer linear programming method to solve the optimal scheduling model of the integrated energy system in buildings is proposed. The correctness and validity of the proposed model are verified by analyzing the load optimization effect, cost, and related influencing factors of buildings in a certain region under different scenarios.