A laboratory experiment for studying the effects of sediment dredging on denitrification process was carried out through a one-year incubation of undredged sediments (control) and dredged sediment cores. Denitrification rates in the sediments were estimated by means of the acetylene blockage technique. During the experiments, the denitrification rates in the undredged and dredged sediments ranged from 21.6 to 102.7nmol/(g·h) and from 6.9 to 26.9nmol/(g·h), respectively. The denitrification rates in the undredged sediments were significantly higher (P < 0.05) than those in the dredged sediments throughout the incubation period, with an exception of February 2006. The relative importance of various environmental factors on denitrification was assessed, and the results indicated that denitrification rates in both undredged and dredged sediments were regulated by temperature controls. Nitrate was likely to be the key factor limiting denitrification rates in both undredged and dredged sediments. Organic carbon played some role in determining the denitrification rates in the dredged sediments, but not in the undredged sediments. Potential denitrification in the early dredged sediments couldn't reach a high rate as that in undredged sediments, which should be considered as a potential negative effect for nitrogen removal.