One field experiment was conducted in the yellow Chinese chive production system on north bank of Dianchi Lake to investigate the effects of reducing amount of nitrogen fertilizer and the application of Dicyandiamide(DCD)on losses of nitrogen from the vegetable field.Results indicated that the treatment of decrease of N by 20% reduced the TN content of leaching,lateral leaching and runoff by 37.0%,22.2% and 28.9% respectively;the treatment also reduced the nitrate content of yellow Chinese chive by 13.6% and had no obviously effect on its yield.The application of DCD on the base of reducing nitrogen reduced the TN content of leaching,lateral leaching and runoff by 58.4%,59.7% and 17.1% respectively.While it increased the yield of yellow Chinese chive by 8.7% and reduced its nitrate content by 24.8%.Therefore,reducing the amount of nitrogen fertilizer and applying DCD may be important measures to reduce nitrogen losses from the Yellow Chinese Chive fields and reduce the nitrate content of yellow Chinese chive.The technique would have important practical significance and be of good popularization value.in the study area.