Based on a simulative experiment and a comparison analysis, the effect of bivalve Corbicula fluminea activity on sediment-water exchange of dissolved inorganic nitrogen (DIN) is studied.The areas included three intertidal flat sites of the Changjiang (Yangtze) River estuary in China. The interface exchange flux of ammonium, nitrate and nitrite in the short experiment (6 h) was -46.4-40,fluminea increased NH+4 and NO-3 release from sediments to overlying water in the short-term experiment. During long-term incubation, NH+4 and NO-3 released in turn from the sediments. At the beginning of incubation, bioturbation by C. fluminea could accelerate NH+4 release from sediments 2-17 times in different sites, resulting in stronger nitrification and increased NO-3 concentrations in the overlying water. Sediment profile analysis post-incubation shows that organic matter mineralization and sediment-water NH+4 exchange had been stimulated by C. fluminea bioturbation and bioirrigation during the experiment. Therefore, C. fluminea activities such as excretion, burrowing, irrigation and turbation can effectively alter nitrogen dynamics and accelerate and stimulate nitrogen exchange and cycling at the sediment-water interface.