地下水作为张家口地区的主要供水水源，近年来受人类活动影响水质有恶化的趋势，影响了当地的用水安全，确定地下水化学特征与水质状况对水资源合理利用具有重要意义。基于2020年水质数据，选取Ca²⁺、Mg²⁺、K⁺、Na⁺、HCO₃^-、TH、pH、TDS、、Cl^-、Al³⁺、NO₃^-、F^-、Cr⁶⁺等水质因子，通过数理统计法、Piper三线图、Gibbs图和岩石风化端元图对张家口柴宣盆地地区浅层地下水水化学特征进行分析，并采用模糊综合评价和改进内梅罗指数法对水质进行评价。结果表明：研究区地下水是Ca²⁺和HCO₃^-为主的弱碱性淡水，微硬水、硬水和极硬水分别占39.51%、34.57%和25.93%；沿地下水流向，地下水化学类型由HCO₃-Ca·Mg、HCO₃-Na、SO₄·Cl-Na型转变为HCO₃-Ca·Mg、HCO₃-Na、SO₄·Cl-Ca·Mg型，水化学组分的空间分布特征主要受到硅酸盐、碳酸盐的风化溶解和人类活动影响；地下水水质整体满足III类标准，但部分地区水质较差；沿着地下水流向，水质逐渐变差，主要受原生地质环境和工业、农业污染的影响。

As the main water supply source in Zhangjiakou area, the water quality of groundwater has deteriorated in recent years due to human activities, which has affected the local water safety. It is of great significance to find out the chemical characteristics and water quality of groundwater for rational utilization of water resources. Based on the water quality data of 2020, Ca^{2 +}, Mg²⁺, K⁺, Na ⁺, HCO_3-, TH, pH, TDS, , Cl^-, Al³⁺, NO₃^-, F^-, Cr⁶⁺ were selected as water quality factors. The hydro-chemical characteristics of shallow groundwater in the Chaixuan Basin of Zhangjiakou were analyzed by mathematical statistics, Piper diagram, Gibbs diagram and endmember diagram of rock weathering. The groundwater quality was evaluated by fuzzy comprehensive assessment and improved Nemerow index method. The results show that the groundwater in the study area is weakly alkaline freshwater dominated by Ca²⁺ and HCO₃^-, of which micro-hard water, hard water and hardest water account for 39.51%, 34.57% and 25.93%, respectively. The hydro-chemical types change from HCO₃-Ca·Mg, HCO₃-Na, SO₄·Cl-Na to HCO₃-Ca·Mg, HCO₃-Na, SO₄·Cl-Ca·Mg along the groundwater flow direction. The spatial distribution characteristics of hydro-chemical components are mainly affected by the weathering and dissolution of silicate and carbonate and human activities. The groundwater quality meets the standard of Class III on the whole, but the groundwater quality in some areas is poor. Along the flow direction of groundwater, the water quality gradually deteriorates, which is mainly affected by the primary geological environment and industrial and agricultural pollution.