With the innovation and development of science and technology， the Internet of Things is more and more used in daily production and life， in order to support the development of the Internet of Things industry， the relevant departments have issued a number of policies， including technology research and development， standard formulation， application promotion， information security and so on. This paper mainly describes the application of the Internet of Things in the building field （such as intelligent security， intelligent fire protection， energy management， parking management， environmental monitoring， etc.）， and introduces the great potential and practical role of the Internet of Things technology in optimizing building functions， energy saving and emission reduction.