Change in distribution of C, N, P and K in particlesize fractions of a cultivation chronosequence of paddy soils in subtropical China was investigated by particlesize fractionating with the sedimentation method Results show that contents of organic C, N, P and K in various fractions decreased with increasing particle size, and that their distribution in the fractions varied significantly in percentage. Organic Carbon in fractions of<0.002 mm, 0.002~0.02 mm, 0.02~0.05 mm and >0.05 mm accounted for 29.2%, 30.7%, 11.9% and 15.4%, N for 36.7%, 31.9%, 10.2% and 14.0%, P for 49.2%, 26.5%, 11.1% and 12.4%, and K for 36.9%, 33.4%, 12.9% and 20.0%, respectively of the total in the soil. Generally, a high percentage of organic C, N, P and K was distributed in clay and silt as well. Besides, their distribution in the fractions differed obviously with the cultivation history of paddy soils. In paddy fields less than 10 years in rice cultivation, the contents of soil organic C, N, P and K were relatively lower and mainly distributed in Fraction<0.002 mm, whereas in paddy fields more than 10 years in rice cultivation, the distribution of organic C and nutrients in silt (0.002～0.05 mm) exceeded 50%. Silt (0.02～0.05 mm) was also the highest in C/N ratio regardless of cultivation history, but it did decrease with rice cultivation going on, which suggests that the observed changes indicate improvement of soil fertility and soil nutrient availability.