With the advancement of urbanization, the urban management is shifted from "extensive" to "refined". The major municipal facilities in city are the important factor to ensure the safety of city operation. The digital transformation of municipal facilities is not only the need of urban refined management, but also an important support to promote the modernization of urban governance. Combined with the construction experience of intelligent management platform for major municipal facilities in mega cities, five types of major municipal facilities in city such as urban road and its facilities, underground pipelines, garbage treatment facilities, sewage treatment facilities and emergency fire protection facilities are classified and sorted out. The information coding system of the major municipal facilities in city with management components, management events and sensors as the core is built to ensure the standardization of perception data collection for major municipal facilities in city, and promote "one-network unified management" of major municipal facilities in city.