Based on the water quality data collected at 14 monitoring sections from 2008 to 2012,the variation characteristics of water quality in the Han River and Dan River of Shaanxi region were analyzed using the methods of single factor pollution index, average comprehensive pollution index and Spearman's rank correlation coefficient. The results indicated that,the water quality in the Han River and Dan River of Shaanxi region were excellent and almost all of the cross-sections were matched up to the categoryⅡor the category III according to national standards of surface water ( GB 3838—2002 ) . The extent of average comprehensive pollution index of the water in the region declined significantly during the five years. Especially, the average comprehensive pollution in Han River showed an evident decrease during the period of time in this study. At the same time, the variation of average comprehensive pollution index of the water exhibited regional characteristics in their spatial distribution. Generally,the comprehensive pollution levels in urban reach were higher than that in suburban reach,and it was more polluted in the downstream than the upstream in the region. In addition, it appeared that the water quality was mainly affected by organic pollution and eutrophication factor. It was also found that the water pollution in the region mainly come from the domestic sewage and agricultural non-point sources,and industrial wastewater contributed little and concentrated in a few key industries.%基于2008—2012年陕西省境内汉江、丹江干流14个断面的水质监测数据，采用单因子评价法、平均综合污染指数法和秩相关系数法等对该段水体的水质变化特征进行研究。结果表明，汉丹江(陕西段)断面水质以Ⅱ类、Ⅲ类为主，水质总体为优；水质综合污染状况呈下降趋势，其中汉江下降趋势显著；水质综合污染状况空间差异和区域分布特征明显，城区段污染大于郊区，各行政区段河流下游污染大于上游。流域水质主要受有机污染和营养盐因子影响，水体污染源主要来自城镇生活源和农业面源，工业源占比不大且排放行业较为集中。
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