Undisturbed sediment cores from four sites in Meiliang Bay were collected from north to south of Lake Taihu, thenincubated by flow-through technique in the laboratory. The denitrification and anaerobic ammonium oxidation (anammox) rates weremeasured by stable isotope tracing technique, isotope nitrogen product measurement and isotope pairing technique. The resultsshowed that denitrification and anammox rate were from 46.36±13.26 to 16.34±22.74μmol/(m²·h) in the Meiliang Bay and from7.50±2.21 to 2.05±2.90μmol/(m²·h) on the open lake areas out of the bay, respectively. Denitrification rates were significantly higherin the north of the Meiliang Bay than in the south and open lake areas. The dominated nitrogen removal process was uncouplednitrification-denitrification(Dw) which utilizing nitrate in overlying water as substrate in north Meiliang Bay, and coupleddenitrification(Dn ) was dominate process in the open lake area. The concentration of NO₃^-and O₂penetration depths were mainfactors affecting the distribution of Dn and Dw . The anammox proportion of the total nitrogen removal ratio was 12%-14% in theMeiliang Bay, and 11% out of the bay, which was correlated with the denitification rate and influenced by the intermediate product(nitrite) of denitrification.