Sulfur-based　autotrophic　denitrification　(SADN)　offers　new　pathway　for　nitrite　supply.　However,　sequential　transformation　of　nitrogen　and　sulfur　forms,　and　the　functional　microorganisms　driving　nitrite　accumulation　in　SADN　with　different　reduced　inorganic　sulfur　compounds　(RISCs),　remain　unclear.　Desirable　nitrite　accumulation　was　achieved　using　elemental　sulfur　(S0-group),　sulfide　(S2--group)　and　thiosulfate　(S2O32--group)　as　electron　donors.　Under　equivalent　electron　supply　conditions,　S2O32--group　exhibited　a　superior　nitrate　conversion　rate　(NCR)　of　0.285　kg　N/(m3　&　sdot;d)　compared　to　S2--group　(0.103　kg　N/(m3　&　sdot;d)).　Lower　NCR　in　S2--group　was　attributed　to　sulfide　strongly　inhibiting　energy　metabolism　process　of　TCA　cycle,　resulting　in　reduced　reaction　rates.　Moreover,　the　NCR　of　S0-group　(0.035　kg　N/(m3　&　sdot;d))　was　poor　due　to　the　chemical　inertness　of　S0.　Specific　microbial　communities　were　selectively　enriched　in　phylum　level,　with　Proteobacteria　increasing　to　an　astonished　96.27-98.49　%.　Comprehensive　analyses　of　functional　genus,　genes,　and　metabolic　pathways　revealed　significant　variability　in　the　active　functional　genus,　with　even　the　same　genus　showed　significant　metabolic　differences　in　response　to　different　RISCs.　In　S0-group,　Thiomonas　(10.0　%)　and　Acidithiobacillus　(5.1　%)　were　the　primary　contributor　to　nitrite　accumulation.　Thiobacillus　was　the　most　abundant　sulfur-oxidizing　bacteria　in　S2--group　(43.84　%)　and　S2O32--group　(18.92　%).　In　S2--group,　it　contributed　to　nitrite　accumulation,　while　in　S2O32--group,　it　acted　as　a　complete　denitrifier　(NO3--N　-＞　N2).　Notably,　heterotrophic　denitrifying　bacteria,　Comamonas　(12.52　%),　were　crucial　for　nitrite　accumulation　in　S2O32--group,　predominating　NarG　while　lacking　NirK/S.　Overall,　this　work　advances　our　understanding　of　SADN　systems　with　different　RISCs,　offering　insights　for　optimizing　nitrogen　and　sulfur　removal.