Abstract: In response to the lack of research on the groundwater quality and ecological environmental effects in the ecological coordinated control zone of the alluvial plain at the northern foothills of the Qinling Mountains, taking the main body of the northern foothills - Xi'an section as an example, based on 107 shallow groundwater samples collected from December 2023 to January 2024, this study explains the hydrochemical characteristics and formation mechanism of groundwater through Piper's trilinear diagram, Gibbs diagram, and the relationships between major ions. According to the Quality Standards for Groundwater (GB/T 14848-2017), the quality of groundwater, factors exceeding standards, and associated ecological and environmental issues are identified. The results show that the groundwater is weakly alkaline and belongs to freshwater as a whole. The main controlling anions and cations are HCO₃^- and Ca²⁺, respectively; and the dominant hydrochemical types are HCO₃-Ca, HCO₃-Ca·Mg, HCO₃·SO₄-Ca·Mg, HCO₃·SO₄-Ca and HCO₃-Ca·Na. The hydrochemical characteristics of groundwater are mainly influenced by the dissolution of silicate rocks and carbonates, cation exchange, and human activities. The water quality grades II, III, IV, and V of groundwater account for 15.89%, 52.34%, 11.21%, and 20.56%, respectively; and the main factors causing substandard water quality are nitrate and total hardness. The groundwater quality in the front of the Qinling Mountains is relatively good, while the groundwater quality in the plain areas is relatively poor, therefore it is urgent to control point source pollution, reduce non-point source pollution, and carry out groundwater environmental governance. The research findings are of great significance for strengthening the development, utilization, and protection of groundwater resources in the Qinling Mountains.