Abstract: The uptake kinetics parameters play an important role in screening nutrient-efficient genotypes since they could be used to evaluate the ability to uptake nutrient.The potassium uptake kinetics by different genotype under different K nutrition status was studied using greenhouse water culture.The results showed that there was a difference between the dynamic of depletion by different genotype wheat,and the depleting speed of efficient genotype was high while the speed of the inefficient genotype was low.K+ uptake kinetics parameters Km and Imax could be used to evaluate the differences of low K stress tolerant abilities for different genotype wheat.The results classifying with K+ uptake kinetics parameters Km and Imax under different K nutrition condition were corresponding with that of different K efficiency wheat screening.However,Km and Imax of different genotype wheat behaved differently under different K status,the value of which was influenced by the nutrition condition of wheat itself.With the increase of K level,the value of Km increased whereas(Imax) decreased,but some genotypes were influenced relatively largely and the others small,whereas there was still a law generally.W6-986 and ZM13 were potassiumefficient genotypes,and YN 015 was a kind of potassium-inefficient genotype.The same genotype wheat might uptake K+ with different physiology mechanism under different K nutrition status.