流域多级数据底板是数字孪生流域构建的基础，其核心是整合多源、多尺度、多层级的地理空间数据，以支撑流域预报、预警、预演、预案功能的准确有效应用。针对多级流域地理存在的数据量大、几何和色彩不一致、整合不充分等问题，以飞来峡水利枢纽数字底板建设为例，探讨了多级数据底板融合的关键技术。从数据存储管理、空间配准、拓扑融合、色彩统一处理和高效渲染等多个角度，实现了多级数据底板的有效融合与应用，提升了地理空间数据在流域规划、设计、建设和管理等水利全生命周期业务中的支撑作用，为其他流域的地理空间大数据平台建设提供了参考。

The multi-level data baseboard for watershed is fundamental for constructing digital twin watershed, integrating multi-source,multi-scale and multi-tier geospatial data to support the accurate application of forecasting, warning, simulation, and planning functions. Addressing issues such as large data volumes, inconsistencies in geometry and color, and insufficient integration in multi-level watershed geospatial data,taking the digital baseboard construction of Feilaixia Water Conservancy Hub for example, we explored key fusion technologies for multi-level data baseboards. We achieved the effective integration and application of multi-level data baseboards from data storage management, spatial registration, topological fusion, color unification, and efficient rendering, which could enhance the supporting role of geospatial data throughout the full lifecycle of water conservancy management, from planning and design to construction and maintenance, providing guidance for geospatial big data platform construction for other watersheds.