Abstract: Tighteen different rice varieties were screened and evaluated for low potassium stress (5 mg/L) and normal (40 mg/L) in hydroponic culture at seedling stage by adopting relatively low potassium tolerance index and variance and principal component analysis method. Variance analysis showed that there was significant or very significant differences in 16 potassium efficiency related traits among 18 rice genotypes. Principal component analysis showed that the accumulation contribution rate for first five principal components reached 90.972%, which implied that they contained most of the information to reflect the all trait resource. The proportions of relative plant dry weight, shoot dry weight, root dry weight, root/shoot ratio, shoot potassium uptake and plant potassium uptake in the five principal components were higher, so they could be used as screening index of rice potassium efficiency germplasm resources screening at seedling stage. The comprehensive evaluation results showed that the highest score (2.2753) was Zhanyou 2009冶and the second was Teyou 524冶(2.2545), both were the best potassium tolerance rice varieties; Huangfengzhan, Huanghuazhan, Boyouwan3, you3550 etc. were medium potassium tolerance varieties; the least score (-1.8583) was Boyou043冶, it was low potassium sensitive varieties.