The problem of soilnitrogen(N)leaching caused by unreasonable water and fertilizer management practices is more seriously in open-field vegetable planting areas. In order to reveal nitrogen characteristics and control effects underdifferent water and fertilizer management measures，a field experiment with cucumber -Chinese eggplant rotation was conducted in a typical open field for vegetable planting in north China. The characteristics of N leaching were studied usingthe lysimetermethod.1)The total Nleaching(TNL)value under the conventional N application rate[890kg/(hm²·season)]was 307.5 kg/hm² for the entire vegetable year and it had a significantly positive correlation with the N application rate.2)Reduction of the N rate by 20% and 50% decreased the TNL by 12.8% and 36.3% during the entire cucumber and eggplantseason(including the fallowperiod)，respectively.3)A 20% reduction in the N rate had no obvious impact on vegetable yields. An amendment with a urease-inhibitor plus a nitrification-inhibitor，biochar，and straw decreased TNL by 3.7%～10.4%，compared to that without amendments.4)A combined reduction of N and the irrigation rate by 20% showed adecrease of the TNL by 33.4%.5)Since the base fertilization was applied to the ridge line and covered with soil whichavoiding the direct N leaching at the furrow，replacing 35% N with organic manure did not show significant effect on N leaching. The results showed that N leaching substantially contributed to the loss of fertilizer N in a typical open-fieldvegetable field in northChina，under the condition of large amount of water and fertilizer . Appropriate management practices can effectively reduce the TNL at different degrees without the negative impact on vegetable yields. These practices includethe addition ofsynergists(urease inhibitors and nitrificationinhibitors)，the amendment withbiochar，and the reduction in both N rate and irrigation volume by 20%.