Sulfitobacter　sp.　TCYB15,　a　sulfur-oxidizing　bacterium,　was　isolated　from　the　gills　of　Bathymodiolus　marisindicus　at　Tiancheng　hydrothermal　vent.　In　this　study,　the　whole　genome　of　Sulfitobacter　sp.　TCYB15　was　analyzed.　And　its　metabolic　characteristics　and　potential　adaptation　mechanisms　were　discussed.　The　results　showed　that　the　complete　genome　of　strain　TCYB15　was　3,640,800　bp　in　length　with　the　60.5　%　G　+　C　content.　One　chromosome　and　four　circular　plasmids　were　present.　It　contained　3536　coding　genes　and　56　non　coding　genes　(including　9　rRNAs,　47　tRNAs).　Sulfitobacter　sp.　TCYB15　had　multiple　sulfur　metabolism　traits　that　allowed　it　to　acquire　energy　in　the　hydrothermal　environment.　One　pair　of　luxI/R-type　quorum　sensing　gene　was　annotated　and　two　AHL　signal　molecules　(C6-HSL　and　C8-HSL)　were　identified.　A　series　of　genes　involved　in　biofilm　formation,　exopolysaccharide　production,　flagella,　chemotaxis,　and　resistance　to　heavy　metals　and　osmotic　stress　were　found　to　adapt　to　extreme　environments.　This　study　could　shed　light　on　the　genetic　basis　of　potential　survival　strategies　employed　by　Sulfitobacter　sp.　TCYB15　in　hydrothermal　environments.