To explore the effect of controlling drainage on soil nitrogen loss, nitrogen fertilizer use efficiency and yield in oil sunflower farmland, the growth period control drainage depth was set to be 40cm (K1), 70cm (K2), and 100cm (K3), open ditch drainage was chosen as the control treatment (CK), and field trials were carried out. The results showed that the soil NH+4N content of K1 treatment was the highest, with an average value of 20.17mg/kg, which was significantly higher than that of other treatments（P<0.05), and was 31.36%, 46.16%, 15.22% higher than that of K2, K3 and CK treatments. The NO-3N content of 0~40cm soil after irrigation during the growth period showed the trend from large to small as K1, CK, K2 and K3. The loss of NO-3N in different treatments was greater than that of NH+4N. The loss of NO-3N in K1, K2, K3 and CK treatments was 60%, 52.63%, 30.77% and 58.82% higher than NH+4N, respectively. For the subsurface drainage treatment, the smaller the outlet depth was, the smaller the drainage and the nitrogen loss were, and the control of drainage stabilized the change of groundwater depth. The controlled drainage treatment (K1, K2) increased the partial productivity of nitrogen fertilizer by 3.04% ~ 11.15%, and increased nutrient absorption. The partial productivity of nitrogen fertilizer in K1 treatment was the largest, which was increased by 4.54%, 7.72% and 11.15% compared with K2, K3 and CK treatments respectively（P<0.05). K1 treatment can significantly increase corn yield（P<0.05), which was 4.52%, 7.69% and 11.14% higher than that of K2, K3 and CK treatments, respectively. After the oil sunflower was harvested, the NH+4N content of 0~100 cm soil in each treatment was 0.98~8.13mg/kg, and the soil NH+4N content was decreased with the increase of soil depth, the soil NH+4N content in 0~40cm soil layer of CK treatment was the largest, which was 11.65%, 14.55% and 18.19% larger than that of K1, K2 and K3, respectively（P<0.05). The NO-3N content in the same soil layer under the same treatment was significantly higher than the NH+4N content. After irrigation during the growth period, the NO-3N in the 0~10 cm soil would flow to the deep soil with water, while most of the NO-3N in the K1 treatment would be accumulated in the 20~40cm soil layer. In the middle and late stages of growth, the 20~40cm soil layer was the vigorous oil sunflower root layer, and the K1 treatment had relatively high nitrogen utilization in the soil. Considering oil sunflower yield, soil nitrogen change law, nitrogen fertilizer use efficiency and nitrogen loss, the suitable drainage method was to control the drainage depth of 40cm during the growth period (K1).