With the continuous emergence of new technologies and the efficient and convenient development of people’s daily life and work, the topic of intelligent building is becoming more and more hot. There are two kinds of data in intelligent building, namely static data and dynamic data. The digital expression of intelligent building is realized through the fusion and interaction of these two kinds of data. The building information model (BIM) stores a large amount of static data, including size, material, color and other data, while the Internet of Things (IoT) collects real-time dynamic data, including temperature, humidity, light and other data, through sensors in every space within the building. The related problems of building data management in the design and operation and maintenance stages mainly include data collection relying on manual work, low data processing efficiency, scattered and disorderly data storage, difficult data interaction, slow speed, and low data visualization. In order to solve these problems, this paper combines the characteristics and advantages of BIM and IoT technology, analyzes the interaction and application value of BIM and IoT technology in the design and operation and maintenance stage of intelligent buildings, and constructs a data management system based on the Internet of things, a 3D visualization technology based on BIM, and an operation and maintenance management platform based on BIM and IoT. The application of BIM and IoT technology in the design and operation and maintenance stage of intelligent buildings has promoted the development of the construction industry. The Internet of Things can provide many functional services, such as real-time monitoring, remote tracking, automatic update, plan management and a series of personalized services and management, to achieve the management, control and detection of various things, and ensure the high-speed and effective operation of the system. The emergence of the building system of modern communication network technology has brought many conveniences to people, and there is still a broad space for development. The combination of new Internet of Things technology and intelligent buildings will certainly be an important development direction.