Anaerobic　ammonia　oxidation　(Anammox)　coupling　sulfur　autotrophic　denitrification　is　an　effective　method　for　the　advanced　nitrogen　removal　from　the　wastewater　with　limited　carbon　source.　The　influence　of　S2O32--S　addition　on　Anammox　coupling　sulfur　autotrophic　denitrification　was　investigated　by　adding　different　concentrations　of　S2O32--S　(0,　39,　78,　156　and　312　mg/L)　to　the　Anammox　system.　The　contribution　of　sulfur　autotrophic　denitrification　and　Anammox　to　nitrogen　removal　at　S2O32--S　concentrations　of　156　mg/L　was　75%　similar　to　83%　and　17%similar　to　25%,　respectively,　and　the　mixed　system　achieved　completely　nitrogen　removal.　However,　Anammox　bioactivity　was　completely　inhibited　at　S2O32--S　concentrations　up　to　312　mg/L,　and　only　sulfur　autotrophic　denitrification　occurred.　The　isotopic　effects　of　NO2--N　(delta　N-15(NO2)　and　delta　O-18(NO2))　and　NO3--N　(delta　N-15(NO3)　and　delta　O-18(NO3))　during　Anammox　coupling　sulfur　autotrophic　denitrification　showed　a　gradual　decrease　trend　with　the　increase　of　S2O32--S　addition.　The　ratios　of　delta　N-15(NO2):delta　O-18(NO2)　and　delta　N-15(NO3):delta　O-18(NO3)　was　maintained　at　1.30-2.41　and　1.36-2.52,　respectively,　which　revealed　that　Anammox　was　dominant　nitrogen　removal　pathway　at　S2O32--S　concentrations　less　than　156　mg/L.　Microbial　diversity　gradually　decreased　with　the　increase　of　S2O32--S.　The　S2O32--S　addition　enhanced　the　S2O32--driven　autotrophic　denitrification　and　weakened　the　Anammox,　leading　to　a　gradually　decreasing　trend　of　the　proportion　of　Candidatus　Brocadia　as　Anammox　bacteria　from　the　initial　27%　to　4%　(S2O32--S　of　156　mg/L).　Yet　Norank-f-Hydrogenophilaceae　(more　than　50%)　and　Thiobacillus　(54%)　as　functional　bacteria　of　autotrophic　denitrification　obviously　increased.　The　appropriate　amount　of　S2O32--S　addition　promoted　the　performance　of　Anammox　coupling　sulfur　autotrophic　denitrification　achieved　completely　nitrogen　removal.