Abstract: The experiments of soil culture with different potassium(K) levels were carried out to study K absorption and its physiological and biochemical characteristics of K-efficient barley genotype. The results show that K content of the K-efficient barley genotype(Sandrime)is lower than that of the K-inefficient genotype(AC Westech)under the K levels, while biomass of the K-efficient barley genotype is significantly higher than that of the AC Westech(p＜0.05). At seedling and tillering stages, the biggest differences in biomass of these two genotypes are 2.4 times and 2.1 times respectively. Root vigor of the K-efficient barley genotype is lower than that of the AC Westech. The chlorophyll contents of the two genotypes reach their maximums when the K is offered normally, and the chlorophyll content of the K-efficient genotype is higher than that of the K-inefficient genotype. SOD activity of the K-efficient genotype is higher than that of the K-inefficient genotype, and the biggest difference is 2.74 times at seedling stage, and 3.26 times at tillering stage. However, POD activity of the K-efficient barley genotype is lower than that of the K-inefficient genotype, and the biggest difference is 2.94-4.98 times at seedling stage and 2.12-2.76 times at tillering stage. MDA and soluble sugar contents of the K-efficient genotype are lower than those of the K-inefficient genotype at the two stages.