【Objective】 As an essential biochemical process in soil, mineralization of soil organic carbon (SOC) is closely related to release of soil nutrients, maintenance of soil quality, and formation of greenhouse gases. Mineralization of soil organic carbon varied in characteristic with soil properties and environment, while fertilization and groundwater table are two key environmental factors affecting soil properties. The objective of this study is to explore dynamics and characteristics of SOC mineralization in red paddy soil under long-term fertilization relative to pattern of the fertilization and groundwater table, in an attempt to provide certain guidance for rationalizing nutrient management programs. 【Method】A long-term field experiment, initiated in 1982, was designed to have 3 fertilization treatments (2/3OM, 1/3OM and NPK) and 2 groundwater tables (at 20 cm and 80 cm in depth). In Treatment 2/3OM organic manure was applied at a rate to make up 2/3 of the total N supply; in Treatment 1/3OM organic manure at a rate to make up 1/3; and in Treatment NPK, Urea to make up the total N supply. In all the 3 treatments, P and K was applied the same in rate. Each treatment had 3 replicates. Soil samples were collected from the topsoil layer, 0–10 cm in depth, before ploughing in 2017. Cumulative emission and mineralization rate of carbon dioxide were determined with the incubation method. First-order kinetic model was used to calculate potential mineralization and turnover rates. 【Result】Groundwater table had a significant impact on characteristics of organic carbon mineralization; SOC content in Treatment 2/3OM, 1/3OM and NPK was 20.66%, 23.30% and 17.97%, respectively, higher when the groundwater table was at 20 cm in depth than when it was at 80 cm in depth; Mineralization rate, cumulative mineralization and potential cumulative mineralization (C₀) of SOC in Treatment 2/3OM and 1/3OM was also higher in the former case than in the latter case, whereas in Treatment NPK reverse tendencies were observed; Obviously mineralization of SOC in red soil varied significantly with fertilization pattern and depth of groundwater table. In terms of content, mineralization rate and cumulative mineralization of SOC, the three treatments exhibited an order of 2/3OM>1/3OM>NPK. When the groundwater table was at 20 cm in depth, Treatment 2/3OM and 1/3OM was 53.32% and 15.44% higher than Treatment NPK, respectively, in SOC cumulative mineralization rate, but when the groundwater table was at 80 cm in depth, Treatment 2/3OM and 1/3OM was 5.56% and 17.95%, respectively, lower. Meanwhile, in the case of the former, Treatment 2/3OM and 1/3OM significantly higher than Treatment NPK in potential mineralizable soil organic carbon (C₀), but in the case of the latter, Treatment 1/3OM was significantly lower than Treatment NPK, and in the case of the former, the treatments did not vary much in SOC turnover constant (k), whereas in the case of the latter, Treatments 2/3OM and 1/3OM were significantly higher. 【Conclusion】 In conclusion, high groundwater table is conducive to accumulation of soil organic carbon, increase of cumulative mineralization, cumulative mineralization rates and potential cumulative mineralization of SOC in red soil under long-term application of organic manure, but lowers SOC cumulative mineralization rate in the soil under long-term application of chemical fertilizer. The effects of long-term fertilization on cumulative mineralization rate and potential cumulative mineralization of SOC in red paddy soil vary with depth of groundwater table.