【Objective】 Soil organic carbon (C) is distributed heterogeneously in soil aggregates of all size particles. Organic C mineralization is an important biochemical process in the soil ecosystem and is greatly affected by environmental factors, such as temperature. The objective of this study is to illuminate relationship of organic C mineralization in aggregates with that in bulk soil, to evaluate sensitivity of organic C mineralization in soil aggregates to temperature relative to particle size and eventually to help understand mechanisms of the organic C mineralization in soil aggregates and its sensitivity to temperature. 【Method】The soil used in this study was collected from a paddy filed of red soil fertilized with inorganic and organic manure for 20 years in Yujiang Country, Jiangxi Province, China. Five fractions of aggregates, i.e., >2 mm, 1~2 mm, 0.25~1 mm, 0.053~0.25 mm and <0.053 mm, were isolated with the wet-sieving technique. All the aggregates and bulk soil samples were moistened or dried till they reached 60% in water holding capacity and incubated at 15 °C, 25 °C and 35 °C, separately, for 35 d. Emissions of carbon dioxide (CO2) were monitored and measured during this period. 【Result】Macroaggregates of >0.25 mm contained more organic C and total nitrogen (N) than microaggregates of <0.25 mm. C/N ratio in soil aggregates decreased with declining particle size. Mineralization rates of organic C in both bulk soil and soil aggregates decreased rapidly during the first 7 days of incubation, then gradually leveled off till a stable state in the end. In the soils incubated at 25 °C and 35 °C, the fraction of soil aggregates >1 mm was the highest while the fraction of soil aggregates 0.053~0.25 mm was the lowest in cumulative organic C mineralization. What’s more, cumulative organic C mineralization in soil aggregates was significantly or ultra-significantly and positively related to the content of organic C and total N. The fractions, >2 mm and 0.25~1 mm, contributed the most to cumulative bulk soil organic C mineralization, reaching up to 34.6% and 28.8%, respectively, in contribution rate. With rising temperature, mineralization rate, cumulative mineralization and cumulative mineralization rate of organic C in bulk soil and aggregates all increased. Sensitivity of organic C mineralization (Q10) in soil aggregates to temperature varied in the range of 1.38~2.00, and was ultra-significantly and positively related to organic C and total N contents as well as C/N ratio. 【Conclusion】Macroaggregates of >0.25 mm play a key role in organic C mineralization in bulk soil. Temperature rise promotes organic C mineralization in soil aggregates. Sensitivity of organic C mineralization to temperature in soil aggregates is closely related to quantity and quality of organic matter in the aggregates.