Abstract: The Xiaderi River is a tributary of the Zequ River and an important river near the Zeku County, Qinghai Province. As an indispensable part of water resources, groundwater plays a vital role in ensuring the living and production water supply for urban residents and supporting social and economic development. Taking the Zeku County section of the Xiaderi River Valley as the research object, through hydrogeological geophysical prospecting, hydrogeological drilling, and sample collection and testing, this paper investigates the hydrogeological conditions, calculates and analyzes the natural resources and exploitable potential of groundwater in, and provides basic data for the development and utilization of groundwater resources in this area.. According to the calculation, the natural resource amount of phreatic water in the pore of loose rocksthe eastern Xiaderi River Valley of county section is 9441 m³/d, and that in the western Xiaderi River Valley of county section is 1 907 m³/d. The exploitable resource amount of groundwater in the eastern Xiaderi River Valley of county section is 3577.8 m³/d, with a salinity of 0.339 g/L. The water quality is good, the water quantity is abundant, and the exploitation quantity is guaranteed, which can serve as the backup water source for the Zeku county. This evaluation idea has reference value for the evaluation of the groundwater resource of other rivers in this region.