As a pioneering demonstration area in the Guangdong-Hong Kong-Macao Greater Bay Area, The Pearl Bay starting area has already been deployed for the construction of a "smart city" demonstration zone. The Engineering Management Information System of the Pearl Bay Development Authority focuses on the work points of the Administration, serves the construction of the Pearl Bay starting area Project supervision and integrates "operations, management, and decision-making" to achieve the whole process supervision of project approval, design, construction, inspection, and comprehensive evaluation, which builds an information foundation for the subsequent management and operation of smart cities. Based on the concept of data fusion, this paper analyzes the data fusion method and process of the system at the data layer, business application layer, and decision application layer. The system is based on the basic construction procedure and the spatiotemporal data fusion method of map grid, which can provides a certain reference for the data integration design of smart supervision platform for engineering construction in other new districts.