目的:分析和评价2007-2010年新昌江下游地表水水质变化趋势,为进一步改善水质提供科学依据。方法:应用内梅罗指数法对新昌江下游地表水主要污染指标进行水质综合评价并进行趋势分析。结果:新昌江下游地表水中总磷、化学需氧量、氨氮和高锰酸钾指数浓度最大值均出现于2007年,分别为0.63mg/L、104mg/L、19.31mg/L、13mg/L,分类等级分别为劣V、劣V、劣V、V,随后逐渐下降,于2009年下半年基本达到III类水质标准,溶解氧浓度2007年的最低值为2.98mg/L,分类等级为V类,随后逐渐升高于2008年下半年达到I-II类水质标准。内梅罗指数逐渐下降至1以下,达到清洁等级。结论:新昌江下游地表水污染状况趋好,主要污染指标逐渐向好,总体水质状况基本好转。 Objective: To analyze and evaluate the trend of surface water quality in the lower reaches of Xinchang River from 2007 to 2010, and provide a scientific basis for further improvement of water quality. Methods: Nemero’s index method was used to evaluate the water quality of major pollutants of surface water in the lower reaches of Xinchang River and to analyze the trend. Results: The maximum concentrations of total phosphorus, chemical oxygen demand, ammonia nitrogen and potassium permanganate in the surface water of the lower reaches of the Xinchang River all occurred in 2007, which were 0.63mg / L, 104mg / L, 19.31mg / L, 13mg / L , The classification level was inferior V, inferior V, inferior V, V, then decreased gradually, and basically reached Grade III water quality standard in the second half of 2009. The lowest concentration of dissolved oxygen in 2007 was 2.98 mg / L, and the classification level was V Class, then gradually rose to meet the I-II water quality standards in the second half of 2008. The Nemeroc index gradually drops below 1 to a clean level. Conclusion: The surface water pollution in the lower reaches of Xinchang River is getting better, the main pollution indicators are getting better, and the overall water quality is basically improved.