A Field experiment was conducted on 14 genotypes of Brassica napus L. with gradient nitrogen treatments including nitrogen fertilizer application rates of high nitrogen 210 kg/hm2， low nitrogen 70 kg/hm2， and no nitrogen application 0 kg/hm2 to screen nitrogen-efficient varieties of B. napus to reduce the dependence on nitrogen fertilizer and promote the green production. Agronomic traits， seed yield， and nitrogen efficiency related indexes including partial factor productivity of nitrogen （PFPN） and agronomic efficiency of nitrogen （AEN） were measured. The nitrogen efficiency was comprehensively evaluated based on correlation analysis of agronomic traits and classification of nitrogen efficiency types. The results showed that there were more significant differences in the response of different genotypes of B. napus L. to nitrogen under the low nitrogen treatment， with significant differentiation in nitrogen efficiency related indexes. The mean value of PFPN and AEN reached 2.75 times and 2.30 times higher than that under the high nitrogen treatment， respectively. The dual highly-efficient genotypes of B.napus L. with significantly higher seed yield than the average yield of all genotypes tested at corresponding nitrogen rate under the high and low nitrogen treatments were screened. PFPN and AEN were stable and excellent， maintaining high levels under the high and low nitrogen treatments （PFPN≥12 kg/kg， AEN ≥5 kg/kg under the high nitrogen treatment； PFPN≥30 kg/kg， AEN≥10 kg/kg under the low nitrogen treatment）. The low nitrogen-efficient genotypes achieved a PFPN of 50.61 kg/kg and an AEN of 43.92 kg/kg under the low nitrogen treatment. The high nitrogen-efficient genotypes performed prominently only under the high nitrogen treatment. Nitrogen application regulated correlations among agronomic traits， with enhanced the positive correlations between aboveground dry weight， number of siliques， and seed yield under nitrogen application. The proportion of dual highly-efficient genotypes was 28.57%， with stable accumulation of biomass. The low nitrogen-efficient genotypes adapted to the low nitrogen treatment by exhibiting high thousand-seed weight and seeds per silique. It is indicated that dual highly-efficient and low nitrogen-efficient varieties of B. napus L. can provide valuable germplasm for the genetic improvement of nitrogen use efficiency and the development of cultivation strategies to reduce fertilizer and improve efficiency in B. napus L..