Abstract: In order to investigate the influence of field engineering on the nitrogen loss with runoff, the farmland comparative experiments, with different field ditche densities, were designed, and rainfall-runoff and nitrogen loss characteristics were studied. The results showed that compared to the treatment having more field ditches, the runoff sensitivity affected by the rainfall intensity with the treatment having less ditches was weaker, and the runoff peak lagged behind and the larger runoff lasted a longer time, the losses of total nitrogen reduced by 7.44%. Nitrate nitrogen and ammonia nitrogen losses were significant different between the two treatments. In early and peak stages of runoff process, ammonia nitrogen had a bigger proportion to total nitrogen than that at decline stage, while nitrate nitrogen’s proportion had little change in the whole process. The loss of nitrogen loading was linearly related to the runoff. The field with more field ditches reduced water logging obviously, while the field with less field ditches reduced more total nitrogen losses.