Abstract: The construction of water system spatial maps is essential for maintaining ecological balance in the water cycle, optimizing water resource allocation, and enhancing flood control. This study utilizes spatial information, remote sensing, and computer technologies, along with high-precision DEM and remote sensing data, to develop methods for dynamic water system extraction, spatial verification, catchment division, coding, and map generation. A national spatial map database for water systems with drainage areas larger than 10 km² was established. By refining catchment divisions to the fourth, fifth, and sixth levels and modeling spatial relationships, the study supports multi-scale hydrological analysis. Automated generation of schematic maps and multi-level visualization was achieved through standardized symbology. Additionally, a seven-indicator evaluation matrix was proposed to scientifically assess water system characteristics. The results improve data accuracy, enrich small watershed information, and provide strong support for water resource planning and management, contributing to the development of water management informatization.