Aiming at the problem of optimal scheduling of buildings with high energy consumption and fast growth rate, a integrated energy system in buildings including photovoltaic power generation, cogeneration system, gas boiler and energy storage device is constructed. Modeling and analyzing various energy devices in the system, considering the demand response compensation price,taking the lowest building operating cost as the objective function, optimization scheduling model of integrated energy system in buildings based on demand response is established. The particle swarm optimization algorithm based on cloud model is used to solve the model optimization. A simulation is introduced to simulate. The two different modes of participation in demand response,and optimization performance of cloud model particle swarm optimization algorithm and basic particle swarm optimization algorithm are compared. The results show that the cloud model particle swarm optimization algorithm model based on demand response can effectively save the operating cost of the integrated energy system in buildings, and reduce the peak-to-valley difference of grid side load.