Abstract: As a core component of the digital twin platform, the data base plate plays a key fundamental role as an "arithmetic data" in supporting the construction of digital twin water sector. In the visualization of the data base plate, there are still data element standards are not consistent, fusion rendering method is not clear, business scenarios are difficult to support, there is no good solutione for specially how to integrate, build, share and update the large-scale 3D base plate. This paper focuses on the idea of data base plate construction of digital twin water sector, elaborates the multi-level data fusion method and business visualization synchronous mapping technology, and explores the construction and application of visualization model for the entire Huai River basin. The results show that standardized governance of multi-source heterogeneous data and lightweight rendering of visualization models are crucial, not only to support the synchronous mapping of basinal physical entities and digital elements, but also to enhance multi-scenario business decision-making capabilities and to provide data support for basin water security.