Abstract: The formation of groundwater was mainly affected by leaching, evaporation, cation exchange, and mixing in the Kashgar River Basin. The dissolution of gypsum, halite, and fluorite minerals provided important sources of SO42^-, Na⁺, Cl^-, and F^- to groundwater. Ca²⁺ and Mg²⁺ were mainly derived from the dissolution of minerals such as gypsum, feldspar, calcite, and dolomite. Gibbs diagrams show that unconfined groundwater was mainly affected by rock weathering and evaporationconcentration, whereas confined groundwater was predominantly affected by rock weathering in the northern part of the Kezilesu River groundwater system. Unconfined groundwater was mainly affected by evaporationconcentration, while shallow confined water was affected by rock weathering in the Gaizi River groundwater system in the southern part. Cation exchange was stronger in the Kezilesu River groundwater system in the northern part than in the Gaizi River groundwater system in the southern part. In general, cation exchange gradually increased with aquifer depth downward. Mixed action occurred both between the surface and groundwater, and also among different aquifers.

Key words: groundwater, hydrochemical characteristics, hydrogeochemical, the Kashgar River Basin, Xinjiang