Differences of N efficiency of oilseed rape (Brassica napus L. )varieties and their physiological properties were studied using a pot experiment and the ratio of seed yield with stressed nitrogen to that with normal N supply was adopted as nitrogen efficiency coefficient. Results showed that the determined nitrogen efficiency coefficient of 8 oilseed rape varieties varied from 0. 37 to 0. 69, the ratio of nitrogen uptake amounts per plant, nitrogen transfer velocity from stems and leaves to seeds, and nitrogen physiological efficiency of oils...