The distribution of soil microbes within soil aggregates is helpful to predict some essential soil biochemical processes. Results varied spatially and temporally because of factors such as climate, soil type, texture and dominant mineralogy as well. Therefore, further research under different climatic conditions and in different soil types needs to be carried out. The paper firstly reported the distribution pattern of microbial biomass in different sizes of water-stable aggregates under long-term different tillages in a subtropical purple paddy soil. Results showed that the distribution pattern of microbial biomass within water-stable aggregates depended on the structures of aggregates themselves, whereas tillage methods had no significant effect on it; Microbial biomass C had no significant differences among soil aggregates while microbial biomass N and water-soluble organic carbon are maximum in the 0.25-0.053mm microaggregates; Combing bridge and no-tillage remarkably increased the content of microbial biomass and water-soluble organic carbon, but had no significant effect on the distribution pattern of microbial biomass and water-soluble organic carbon in soil aggregates.