The smart building system integrates cutting-edge technologies such as BIM, IoT and big data algorithm to realize comprehensive and integrated smart management and control on operation and maintenance of buildings from the aspects of operation management, green energy saving, security supervision, IoT sensing and convenient service. By efficiently connecting software and hardware, the system collects data information of each subsystem in real time, and then carries out data fusion analysis and scenario-based intelligent linkage control to enables instant sensing, accurate judgment and precise execution across the traditional building environment. This scheme can effectively reduce the energy consumption of equipment, and greatly improve property management efficiency and employees' office experience.