Research on nitrogen leaching for two soil types under different nutrient supply and irrigation level was conducted. The
result showed that the leach loss of nitrogen
fertilizer was very different in two soils. The leach loss of nitrogen fertilizer increased with the increase of water and fertilizer supply. Irrigation became the main factor for the leach loss of fertilizer nitrogen, especially the total irrigation capacity, every irrigation amount (soil water holding level) and irrigation times. There was a distinct positive correlation between irrigation and
nitrogen leach loss(P<0\^05). The relation was not remarkable between fertilizer application and nitrogen leach loss at low and medium irrigation level, but remarkable at high irrigation level. When soil moisture kept under 40% of the field capacity on anthropogenic-alluvial soil, the leach amount of fertilizer nitrogen was almost same under all fertilizer application(P>0\^05);There was no discrepancy at nitrogen leach loss between in anthropogenic-alluvial soil with soil moisture ≤40% field capacity and in sandy soil with soil moisture=20% field capacity(P>0\^05), but discrepant under high water and fertilizer treatment. In order to protect environment and improve the efficiency of water-use and fertilizer, the sandy soil should be meliorated under traditional agriculture method(low water and fertilizer level).