Abstract: Saucer-shaped depressions are important areas that have high primary productivity and functions as ecological buffer zones. The hydrological connectivity of saucer-shaped depressions with the inflow rivers and open area of Lake Poyang shows obvious seasonal changes, which influences the nitrogen (N) removal process of the wetlands and thereby can change the volume contribution of wetland N removal to the total N load of Lake Poyang. In this study, N fluxes and removal rates across the sediment-water interface in 9 saucer-shaped depressions of Lake Poyang during the flood and dry period were investigated by conducting sediment core flow-through incubations and using the stable isotope pairing technique. Results showed that, during the flood period, the saucer-shaped depression sediments surrounding the west branch of Ganjiang River exhibited strong respiration and high N removal rates. In contrast, the saucer-shaped depression sediments surrounding Xiushui River showed relatively lower N removal rates, which might be mainly influenced by the level of nitrate (NO3^-) concentrations. During the dry period, the saucer-shaped depression sediments in the two sub-areas showed similar patterns of N fluxes and removal rates, with N removal rates significantly lower than those during the flood period. Overall, the average sediment N removal rate during the flood period was 26.69 ± 12.98 μmol m^-2 h^-1 (12.61-49.50 μmol m^-2 h^-1), of which uncoupled denitrification accounted for 90% ± 11%, and anaerobic ammonium oxidation (anammox) only contributed ~1%. The average sediment N removal rate during the dry period were low, and coupled denitrification accounted for 57% ± 17% of the total sediment N removal. The contribution of anammox to the total sediment N removal during the dry period remained small (4%). The hydrological connectivity of saucer-shaped depressions to the open area and major inflow rivers of Lake Poyang, where higher NO3- loads were shown, can take better advantages of the sediment N removal function of the wetlands, thereby alleviating the N load of the main lake area. Thus, protecting saucer-shaped depressions in Lake Poyang and maintaining its hydrological connectivity with the open lake area and surrounding rivers are important for reducing the N load of Lake Poyang.