In arid regions, oases are critical to human survival and development, relying heavily on groundwater to sustain ecological balance and support socio-economic growth. This study focuses on a representative oasis city, where 198 groundwater samples were systematically collected in September 2022. A suite of analytical methods-including statistical analysis, Piper and Gibbs diagrams, ion ratio analysis, and hydrogeochemical modeling-was used to characterize groundwater chemistry and identify its controlling factors. The results indicate that groundwater in the area is slightly alkaline. Unconfined groundwater is dominated by HCO3 & centerdot;SO4-Ca and HCO3 & centerdot;SO4-Na & centerdot;Ca types, whereas confined groundwater is mainly HCO3 & centerdot;SO4-Na & centerdot;Ca and HCO3 & centerdot;SO4 & centerdot;Cl-Na & centerdot;Ca. Groundwater ion composition is influenced by water-rock interaction, with major ions primarily derived from the dissolution of halite, evaporites, and carbonates; cation exchange processes further affect confined groundwater. Halite and gypsum dissolve, while calcite and dolomite are near dissolution-precipitation equilibrium; overall dissolution propensity is higher in unconfined than in confined groundwater. Hydrogeochemical modeling quantitatively corroborates the primary water-rock interactions inferred from qualitative analyses of groundwater flow. These findings improve understanding of hydrogeochemical evolution in oasis groundwater within arid regions.