Abstract: Using solution cultivation, tested with field experiment, the following paper indicates that the internal potassium use efficiency can judge the rice potassium use efficiency. We investigated some agronomic and nutritional characteristics selected for potassium efficiency in rice, found that the low potassium stress led to decrease in shoot biomass, tillering and root growth, while increase in sodium absorption by root. Under low potassium stress, potassium efficient genotypes had higher growth potential (higher relative dry weight, relative shoot length and relative root length), and higher relative K/Na in shoots and lower in root,and lower relative K/N in shoot and root when compared with the potassium inefficient genotypes.