分析了过滤与堵塞的规律，即过滤时表层堵塞比下层严重．随着过滤运行时间的延续．滤层堵塞由表层逐渐向下层推移；根据反冲洗试验结果，提出了最佳反冲洗强度和最佳膨胀率，并对反冲洗效果进行了实际验证，为正确设计农用砂过滤器提供了设计依据． The law of filtration and plugging was analyzed, that is, the surface clogging was more severe than the lower layer during filtration. With the continuation of the filter runtime. The clogging of the filter layer gradually shifts from the surface layer to the lower layer. According to the results of the backwashing test, the best backwashing strength and the best expansion rate are proposed, and the backwashing effect is verified in practice. This provides a design basis for the correct design of the agricultural sand filter. .