Pot culture experiment was carried out to investigate the effect of soil K level on K contents in various parts of rice plants. The results showed that K content of rice plant reduced gradually during whole growth period. As compared with tillering stage, K content of rice plant decreased by about 69%-75% at maturity stage. Both growing stage and soil K level were the key factors affecting K content of rice plant. At tillering stage, K content of leaf and sheath reduced significantly from top leaf to lower leaves. The ratios of the sheath K content to the corresponding leaf K content were all higher than 1, and the ratios increased accordingly as leaf K content increased. At jointing stage, the similar trend of K content among leaves was also observed as compared with that of tillering stage, but the decrement of K content from top leaf to lower leaves became smaller, and K content ratios of sheath to leaf also reduced, which ranged from 0.26 to 1.49. At full heading stage, K content of upper leave and sheaths was higher than that of lower leave or sheaths when K supply in soil was lower, but K content of lower leave was higher that that of upper leaves when soil K supply was higher. At maturity stage, K content of rice stalk ranged from 2.8 to 22.9 g/kg as the soil K supply increased, while K content of rice seeds remained about 5.0 g/kg. The above results indicated that rice K was preferentially accumulated in upper leaves at tillering stage, and the sheath is the reserve for luxury K uptake, while the lower leave and sheaths were the reserve for luxury K uptake after full heading stage. As rice K content varied greatly among different growing stages and different organs, it’s important to choose the right stage and right organ for rice K status diagnoses. The ratios of sheath K content to corresponding leaf K content is possible a good index for rice K status diagnoses.