Abstract:The impact of agricultural non-point source pollution on environmental safety has surpassed urban living pollution and industrial pollution, and has become the main source of water pollution. The vegetation buffer zone can effectively intercept agricultural non-point source pollutants and reduce the discharge of pollutants into water bodies. Through the collection of domestic and foreign scholars' research results on buffer zones, this paper summarized the research on the ability of buffer zone to reduce agricultural non-point source pollution and the optimal width of buffer zone. The results showed that:(1) The 5 m herb buffer zone had the best interception effect on pollutants. When the buffer zone width exceeded 5 m, it was recommended to use the grass-blown buffer zone, which needed more than 30 m to function. (2) When the buffer zones width was the same, the suspended matter and phosphorus were more easily to be intercepted than nitrogen. The optimal width of the buffer zone for the suspension and phosphorus removal was recommended to be 15 m (reduction rate of 70% or more). But for nitrogen removal, the recommended width was 30 m (the reduction rate was 80%). (3) The interception of pollutants by vegetation buffer zone was affected by many factors such as buffer width, slopes and vegetation types. But the relationships between buffer zone width and reduction rates was not always proportional. When buffer zone width increased to a certain size, the reduction rates of pollutants would not change significantly. The slopes of the buffer zone were not always inversely proportional to the reduction rates. A slight slope could promote runoff infiltration and thus increase the reduction rates of the buffer zone.