Stable isotope tracing and Isotope Pairing Technique (IPT) were used to investigate the effects of bioturbation of Tanypus chinensis larvae in Meiliang Bay, Lake Taihu. The effects included nitrate flux at the sediment-water surface, dissolve oxygen penetration depth, denitrification rate, and the two different pathways, denitrification coupled to nitrification (D_N) and denitrification from overlying water (D_W). Compared to the control, the SOD after Tanypus chinensis added increased from 355.49 ± 131.49μmol/(m²·h) to 546.39 ± 261.41μmol/(m²·h) and from 313.57 ± 61.63μmol/(m²·h) to 554.17 ±184.36μmol/(m²·h) with and without Na¹⁵NO₃ ammended, respectively. The results of nitrate diffusion experiment showed that bioturbation stimulated nitrate diffusion from water to sediment and increase total nitrification rate compared with the non-bioturbated sediment. Total denitrification rate was significantly increased from 31.83 ± 8.79μmol/(m²·h) to 228.98 ± 54.09μmol/(m²·h). D_W was stimulated from15.78 ± 8.51μmol/(m²·h) to 182.96 ±45.22μmol/(m²·h), and D_N from 16.04 ± 5.63μmol/(m²·h) to 46.01 ±8.97μmol/(m²·h). This result showed that zoobenthos bioturbation can stimulate both D_W and D_N, and the D_W was more stimulated than D_N.