In order to investigate the optimal scheme of irrigation and nitrogen application for winter oilseed rape (Brassica napus L.), two-year (2013—2014 and 2014—2015) barrel experiments were conducted to evaluate the effects of different irrigation and nitrogen applications on aboveground dry matter and nitrogen accumulation during reproductive growth stage, seed yield, evapotranspiration (ET) and water use efficiency (WUE), and then determine the yield response factor (Ky) of winter oilseed rape. The experiments included three irrigation levels (W0: (50%~60%)FC, FC denoted field capacity; W1: (60%~70%)FC; W2: (70%~80%)FC) and three nitrogen levels (N0:0g; N1: 1.2g;N2: 2.4g).The results showed that W1N1 could obviously improve aboveground dry matter and nitrogen accumulation during reproductive growth phase, seed yield, and WUE of winter oilseed rape. However, excessive irrigation or nitrogen (W1N2,W2N1 and W2N2) would not significant increase the aboveground dry matter and nitrogen accumulation, seed yield, and WUE in comparison with W1N1. W2N1 achieved the highest seed yield across the two years, while W1N1 obtained the highest WUE. Though no significant differences of seed yield and WUE were found between W1N1 and W2N1, the ET in W1N1 was significantly lower than that in W2N1. In addition, seed yield and WUE were all showed a significant quadratic parabola relationship with ET, and the Ky of winter oilseed rape was 1.36. In comprehensive consideration of seed yield, water and fertilizer conservation, W1N1 treatment was recommended as an appropriate irrigation and nitrogen application schedule for winter oilseed rape in the study area.