Abstract: In order to reduce the discharge of pollutants into the river and promote a virtuous cycle of the aquatic ecological environment, based on the analysis of the mechanism of the ecological safety buffer zone, the authors examined the effect of ecological purification type safety buffer zone technology on the deep treatment of standard tail water in a sewage treatment plant in Nantong City.The results showed that the ecological purification type safety buffer zone technology had a good treatment effect on the effluent of urban sewage treatment plants, with average removal rates of COD_cr, BOD₅, NH₃-N, TP reaching over 52.4%, 50.5%, 52.1%, 53.3%, respectively.The effluent quality can meet the requirements of Class Ⅲ-Ⅳ water in the GB 3838-2002 Surface Water Environmental Quality Standards, and have a broad application prospect in river and lake pollution control.