Abstract: Nitrate leaching in deep unsaturated zone was studied by getting 18 meters soil samples. The result show: nitrate leaching in different fertilizer treatment mainly occurred in 0-4 meter soil layers, the place of nitrate peak went down 0.2-0.6 meters, in high fertilizing field, nitrate leaching was also found in 6.7-8 and 13-15 meters, the more fertilizer used, the more leaching and accumulated nitrate were found in soil profile; Variability of accumulated nitrate in deep unsaturated zone were only found in 4 meter soil profile, especially in root zone soil layer, accumulated nitrate was linear with fertilization, more than 1800 kg/hm2 nitrate were accumulated in the unsaturated zone under root zone.