The　hybrid　bioreactor　combining　sulfate-reducing　ammonium　oxidation　(Sulfammox)　and　Anammox　offered　potential　for　simultaneous　nitrogen　and　sulfur　removal,　but　the　removal　efficiency　and　microbial　mechanism　remain　unclear.　This　study　demonstrated　that　in　the　hybrid　bioreactor,　the　ammonium　utilization　rate　(AUR)　of　Sulfammox　increased　by　5.42　times.　The　promotion　of　NO　2-　on　nitrogen　and　sulfur　conversion　in　Sulfammox　could　be　attributed　to:　1)　Increasing　extracellular　polymers　substance　(EPS)　accelerated　the　stratification　of　granule　sludge;　2)　Increasing　the　relative　abundance　of　Candidatus　Brocadia　by　29.55　times　and　Candidatus　Anammoxoglobus　by　3.17　times;　3)　Upregulating　the　expression　of　nitrification　(amo,　hao　and　nxr)　and　sulfur　metabolism　(sat,　aprAB　dsr　and　sox)　genes,　associated　with　the　pathways　NH4+-*NH2OH-*　NO2--*NO3-　and　SO　4　2--*　S　2--*　SO　4　2-　.　Moreover,　Candida　Brocadia　sapporoensis　emerged　as　a　potential　specie　of　Sulfammox,　mediating　nitrification　by　hao　and　nxr,　and　sulfate　reduction　by　sat　and　aprAB,　thereby　enabling　electron　transfer　between　nitrogen　and　sulfur.