The processes and characteristics of nitrogen mineralization in paddy soils of the Shanghai Region were studied with 120 days anaerobic incubation at 25℃ and 35℃.Results showed that the organic nitrogen mineralized amounted to 4.0% to 9.4% of total N(60 to 241 mg kg^-1) and the mineral nitrogen was only correlated with total N(partial correlation analysis).pH changed greatly and was related to the mineral nitrogen contents during the mineralization.Temperature was one of the main factors influencing the mineralization of nitrogen.Four models,(1) effective cumulated temperature model;(2) a one-component,first order exponential model(one-pool model);(3) a two-component,first order exponential model(two-pool model) and (4) a two-component,mixed first and zero order exponential model including a constant term(special model),were fitted to the observed mineral-N vs incubation days using a non-linear regression procedure.The two-pool model and the special model gave the best fits amongst the four models.The special model was the unique one that could appropriately reflect the responses of organic nitrogen mineralization to incubation temperature in all studied paddy soils.All results showed the special model made the best prediction of nitrogen mineralization under flooded conditions.