To reveal the influence of the salt water intrusion caused by the greenhouse effect on the sediment nitrogen mineralization in the estuary wetland, Cyperus malaccensis marsh sediment samples in the Shanyutan brackish water wetland and the Daoqingzhou freshwater wetland were collected in July, 2015. Using the submerged incubation method, the soil mineralization in different kinds of wetland and salinity effects were examined in the Min River estuary. The results suggested that the sediments in brackish water wetland had a longer nitrogen mineralization time as well as a stronger mineralization capacity under the same incubation conditions. The total inorganic nitrogen (includes ammonia nitrogen and nitrate nitrogen) reached a stable concentration of (499.8±2.1) mg/kg after 70d for Shanyutan brackish wetland sediment, while the mineralization reached equilibrium in only 30d with a lower stable concentration of (202.9±4.1) mg/kg for Daoqingzhou freshwater wetland sediment. Additionally, salinity condition showed little effect on concentration of the total inorganic nitrogen during the mineralization process. The rate of nitrogen mineralization for both brackish and freshwater wetland sediments firstly increased and then decreased as the increase of incubation time. In Shanyutan brackish water wetland, the rate of nitrogen mineralization were (2.54±0.56) mg/(kg·d), (4.96±0.22) mg/(kg·d) and (3.88±0.25) mg/(kg·d) under salinity of 0‰, 5‰ and 10‰, respectively. While in Daoqingzhou wetland, the corresponding values were (1.40±0.01) mg/(kg·d), (2.48±0.15) mg/(kg·d) and (1.85±0.11) mg/(kg·d), respectively. The observation revealed that moderate salinity conditions can promote the nitrogen mineralization, while high salinity conditions could induced an inhibitory effect.