A long-term field experiment was carried out in Jinxian County, Jiangxi Province, China.One of the aims of the experiment was to study soil organic carbon (SOC) distribution in different size groups of aggregates in four horizons (A, P, W₁, W₂) of red paddy soil impacted by different fertilization patterns.The experiment was designed to have four treatments : (1) Zero fertilization (CK), (2) chemical fertilizers alone (NPK), (3) organic manure alone (OM) and (4) combination of chemical fertilizers and organic manure (NPKM).Results show that the percentage of soil aggregates in the size group of >3 mm increased in all horizons, which were in the following order : A > P > W₁ > W₂, but the percentages of the other groups decreased, following the same order.The treatments of NPK, OM and NPKM were in favor of increasing the percentage of aggregates in the size groups of 1～3 mm and 0.25～1 mm.Results also show that the content of SOC in aggregates of the same horizon in all the fertilization treatments decreased in all horizons, showing a sequence of A>P>W₁, W₂.The contents of SOC in different size groups were significantly different and showed an increasing sequence of >3 mm>1～3 mm>0.25～1 mm>0.05～0.25 mm except for the size group of <0.05 mm being the lowest in content.The total content of SOC showed a positively linear relationship with the content of aggregates of the size groups of 1～3 mm and 0.25～1 mm.The storage of total SOC varied between the treatments, showing an increasing sequence of CK>NPK>OM>NPKM.The storages of total SOC in different 2 sized aggregates of the same horizon in the same treatment were also significantly different, showing a decreasing sequence of >3 mm<1～3 mm<0.25～1 mm<0.05～0.25 mm<0.05 mm.The newly enriched organic carbon mostly appeared in the size groups of 1～3 mm and 0.25～1 mm.