With the leaf weight per plant and nitrogen response index as the evaluating index,the low nitrogen tolerance for tobacco germplasms was evaluated,and the relationship between leaf weight per plant,nitrogen response index and main agronomic traits was analyzed.The results showed that most agronomic traits displayed significant differences among different tobacco genotypes under different N-fertilized levels,and most agronomic traits under low N-fertilized displayed the greatest genotypic differences.The difference of leaf weight per plant under different N-fertilized levels was larger than that of the other agronomic traits.Under different nitrogen applying levels,leaf weight per plant was positively correlated with the maximum leaf area and biomass per plant,response index of nitrogen for leaf weight per plant was positively associated with leaf weight per plant and biomass per plant,and the correlation between response index of nitrogen and leaf weight per plan,biomass per plant under low N-fertilized level were higher than that of moderate N-fertilized level.Among these tobacco varieties tested,Yongding 400,Jinyan 6,Hong-hua-da-jin-yuan,G 80 and Nc 82 had the stronger low nitrogen tolerance ability,which could be used as the tobacco varieties of high nitrogen utilization efficiency.