With the development and utilization of urban underground space, the layout of sewage treatment and reclaimed water treatment plants has gradually developed to semi-underground or all-underground. Huaifang Recycling Water Plant is an underground reclaimed water treatment plant built in downtown Beijing to alleviate the pressure of sewage treatment and improve the quality of water environment in the south of Beijing. Relying on the framework of "wisdom" engineering design system, the project explores a new way to combine BIM technology with municipal infrastructure construction. By using BIM technology, the project quality can be fully upgraded, the construction management level can be improved, the information resources can be reserved for the later operation of waterworks, and the public services such as urban infrastructure and urban green space can be provided. The construction and operation of the facility eventually turned the project into the world's largest all-underground recycled water plant, becoming a national model of "smart water plant".