As a basic unit of soil structure and a component of soil fertility，soil aggregate has important influence on its physical，chemical and biological characteristics. Soil aggregate structure and organic carbon distribution of citrus orchard soils with different parent materials were studied by wet sieving method in Yongxing county，Hunan province. The results showed as follows:(1)Soil aggregates with particle size >0.25 mm were dominant in different parent materials，accounting for 85.94%～95.89%，and the content of soil aggregates developed in plate shale weathering was the highest.(2)The size of water stability of soil aggregates in citrus orchard with different parent materials were as follows:plate shale weathering (yellow soil)>quaternary red clay(red and yellow soil)>limestone weathering(gray red soil)>sandy conglomerate weathering(arenosols)>river sediments(river sand and mud).(3)Soil organic carbon content and storage in aggregates，and the contribution rate of aggregate to soil organic carbon were decreased with the decrease of aggregate particle size.(4)The correlation coefficients of mean weight diameter(MWD)，geometric mean diameter(GMD)，fractal dimension(D)and soil erodibility(K)were the largest with >2 mm aggregates，indicating that >2 mm aggregates were the main factors affecting the stability of soil aggregates.(5)The contribution rate of organic carbon of >2 mm soil aggregates was significantly positively correlated with soil aggregate MWD and GMD，significantly negatively correlated with soil K value，and negatively correlated with soil D value. In general，the fertilization management of citrus orchards in south China should focus on increasing organic fertilizer to improve the stability of soil structure and reduce the risk of soil erosion.