Abstract: Potassium absorption and utilization for different cotton varieties were studied based on the screening experiment of seedling stage. The varieties are potassium-efficiency genotypes, Xinluzao 6, Xinluzhong 15, and Xinhai16, and potassium-inefficiency genotypes, Xinluzao 10 and Shik 7. The results show that there are significant differences between potassium content, potassium accumulation and biomass yield of the different cotton genotypes under the two potassium conditions. The Xinluzhong 15 is the best genotype in potassium content, potassium accumulation and biomass yield without potassium application. The qualities of potassium content, potassium accumulation and biomass yield are 1.17 times,1.47 times and 1.25 times of those of Shik 7. Values of the potassium utilization index are different in different cotton genotypes especially under the condition of potassium application. The potassium utilization index of Xinluzhong 15 under the condition of potassium application is 1.40 times, 1.31 times and 1.34 times of that of Shik 7 in 80d 120d and 140d.