Abstract: A field experiment was conducted to study the yield, K uptake and utilization of different late rice varieties under no fertilizer, no potassium fertilizer and high potassium level in order to provide a scientific basis for reasonable potassium application of different late rice varieties in double-cropping paddy area. Fourteen late rice varieties were used as test subjects. The biomasses of different growth stages, the yields of rice and straw were determined. The potassium contents of rice and straw were mensurated and analyzed. The amounts of potassium absorbed by rice plant were calculated. The results showed that grain yields of 14 late varieties for the no fertilizer treatment, non-applying K treatment and applying K treatment were 5053.3 ~ 6813.3 kg/hm2, 6000.0 ~ 8226.7 kg/hm2 and 6240.0 ~ 8106.7 kg/hm2 respectively. The increasing yields of fertilizer application and potassium application were 253.3~ 2040.0 kg/hm2 and -653.3 ~ 546.7 kg/hm2 for each variety of late rice respectively. The amount of potassium absorbed by 14 late rice varieties for the non-applying K treatment and applying K treatment were 91.7~189.8 kg/hm2 and 104.1~170.1 kg/hm2 respectively. The higher potassium contribution rates of ‘Fengyuanyou 272’, ‘Shenyou 9586’ and ‘Weiyou 227’ were 7.01%, 6.69% and 6.96% respectively; the lower potassium contribution rates of ‘Fengyuanyou 299’ was -9.85%. Among the 14 late rice varieties for tested, ‘Fengyuanyou 272’, ‘Shenyou 9586’ and ‘Weiyou 227’ were the potassium-sensitive varieties, which the applying K treatments can make to play greater yields potential; ‘Fengyuanyou 299’ was the potassium deficiency resistant variety, which the applying K treatment can make little yield potential, potash fertilizer can be reduced during rice planting.