Abstract: K content of leaves is an important index of tobacco leaf quality. In order to take full advantage of genetic dominance of K high-efficient genotype and enhance the quality of tobacco leaves, the genotypic difference of K nutrition in flue-cured tobacco, including K uptake rate, low K tolerance, K utilization efficiency and the efficiency of K accumulation, was investigated through a series of soluble planting experiments, pot and field trials. The results showed that there was a significant difference in both K uptake rate and low K tolerance among different genotypes. Hongda and K358 had the greatest K uptake rate. The tolerance of low K of Nc27NF and K358 are the best, while Nc729 was the worst. K content per plant of ten genotypes varied from 0.87% to 1.25% under low K level, but from 1.40% to1.94% under high K level. Among these ten genotypes, the increment of K content of Coker 319, Nc27NF, Nc729 and Hongda was more than 70%. Under the condition of high K level, the augment of K content in leaf of the genotypes G28, 77089-12, Rg11 and K358 was higher than 2%. K358, Coker319, K346, Nc27NF exhibited a higher K utilization efficiency (KUE). K harvest index (KHI) of K346Nc729G28 and K358 was higher than 50%. There was no significant correlation of K nutrition characteristics of different genotypes under different K condition. None but K346 was a K high-efficient genotype according to tradeoff analysis.