A large amount of nitrogenous fertilizer that is not absorbed by crops or evaporated into the air is easily leached transport and accumulated in the shallow vadose zone.The accumulated nitrogen is released again and leached down into subsoils and groundwater,causing pollution.The process is mainly affected by climate,soil structure and microorganism transformation,etc.Knowledge and mastery of the above rules will contribute to exploration of ways to control groundwater contamination from fertilization.A field experiment was carried out to determine nitrogen accumulation in the shallow vadose zone within a year after excessive N fertilizer was applied and the field was irrigated.The results showed that nitrogen accumulation mainly occurred in the shallow vadose zone,1.5 m thick,varied with time,depth and amount of infiltration water.The findings of the research may serve as scientific basis for exploring ways to control groundwater contamination caused by fertilizer application.