The migration characteristics of carbon, nitrogen and phosphorus during organic matter mineralization were studied through laboratory incubation experiments, to simulate Lake Taihu, a large eutrophic lake in China. Results showed that sedimentary organic matter was mineralized and released dissolve inorganic carbon. At the end of incubation, the cumulative contents of CH₄ and CO₂ was 1492.21 mg/g(dw) and 498.96 mg/g(dw), respectively, with CH₄ occupied 89.16% of gaseous carbon (in C mass). In addition, a large amount of nutrients, such as nitrogen and phosphorus, were released into overlying water. The highest concentrations of total nitogen, total phosphorus and ammonium nitrogen were 62.16, 28.16 and 139.45 times of the initial concentration, respectively. While nitrate nitrogen concentration declined throughout the incubation time, and its final concentration was 0.21 times of the initial concentration. Under anaerobic conditions, organic matter mineralization not only produced a large amount of CH₄, CO₂ but also promoted the release of ammonium nitrogen and phosphorus from sediments. These soluble inorganic nutrients further aggravate the lake eutrophication and promote the primary production, with subsequent increasing input of organic matter into lake sediment. This may be one of the important reasons for self-maintenance of lake eutrophication.