he impact of various amounts of nitrogen (N) and potassium (K) nutrient applied at middle and late growing stages on yield and K content of flue-cured tobacco leaf was studied. The experiment was conducted in sand culture and consisted of 16 treatments and four replications. Multiple gradual regression analysis and path analysis results showed that : (1) The yield of flue-cured tobacco leaf was highly positively and significantly correlated with the amount of N applied at middle and late growing stages, and highly correlated with the amount of K applied at middle growing stage; (2) Bottom and upper leaf K contents were negatively significantly correlated with the amount of N applied at middle growing stages, middle leaf K content was negatively correlated with the amount of K applied at late growing stages, and K content for all stalk positions was highly positively and significantly correlated with the amount of K applied at middle and late growing stages; (3) N had a strong direct effect on leaf yield whereas it had a weak effect on leaf K content; (4) K had a strong direct effect on leaf K content, but a weak effect on leaf yield. A balanced application of N and K nutrients at middle growing stage is important for a quality tobacco leaf ; the amount of K nutrient applied should then be increased while the level of N nutrient should be adequately decreased to enhance K absorption and accumulation in plant, and mitigate the dilution effect of leaf K content at growing stage, in order to maintain a high level of K in leaves.