A long-term location experiment of 35 a paddy soil was utilized, with part of fertilization treatments changed to study the characteristics and influences of soil aggregate organic carbon(SAOC) under different fertilization treatments after increasing or reducing the input of organic fertilizer. The results showed that: red paddy soil was dominated by >0.25 mm aggregates; the contents of SAOC under different long-term fertilization treatments was characterized by: >0.25 mm macro-aggregates>0.25-0.053 mm microaggregates>(<0.053 mm)silty clay, meanwhile, the application of organic fertilizer increased organic carbon contents of different sizes of aggregates and the contribution rate of >2 mm aggregate organic carbon. The influence of fertilization on organic carbon of different sizes aggregates was ranked as follows: <0.05 mm <0.25-0.05 mm< (>2 mm)<2-0.25 mm; free iron oxide and chelated aluminum had important effects on organic carbon of 2-0.25 mm aggregates, and free iron oxide played a role in the formation of >2 mm aggregates. Increasing the input of organic fertilizer can increase the organic carbon content of <2 mm aggregates at each grain level, reducing the input of organic fertilizer significantly reduced organic carbon content of aggregates. Regardless of reducing or increasing the input of organic fertilizer, the contribution rate of organic carbon in >2 mm macro-aggregates decreased; at the same time, the contribution rate of organic carbon in <2 mm aggregates after organic fertilizer reduction was increased, and the contribution rate of organic carbon in aggregates of 2-0.25 mm was increased after organic fertilizer application.