Abstract: In the current urban renewal process, the lack of timeliness and completeness of basic data and the failure to implement digital transformation have led to low efficiency in the decision-making process and a large waste of resource allocation. This paper takes the Guangzhou YT urban Village Renovation Project as an example and proposes a digital database construction technology system of "vertical hierarchical detection - horizontal all-domain measurement - digital system" for the decision support of urban renewal in the overall planning of the plot in the early stage. By combining advanced testing technology with the CIM digital management platform, In the aspect of horizontal all-domain monitoring, an analysis and research were conducted on multi-source data such as BIM+GIS+IoT, and the overall architecture and implementation path of digital modeling, planning and decision support were further explored. Research shows that through the CIM digital management platform, project cost reduction and efficiency improvement have been achieved, the decision support capacity has been significantly enhanced, the project management level and operational efficiency have been greatly improved, and the overall control ability has been systematically optimized. This research provides important references and practical basis for in-depth exploration of scientific decision-making and project management in urban renewal.