Reducing　the　sulfur　content　in　high-sulfur　petroleum　coke　(HSPC)　to　below　3.0　%　is　a　big　challenge　for　refineries　to　meet　environmental　policy　and　legal　requirements　in　China.　The　HSPC　examined　in　this　study　has　a　high　sulfur　content　of　7.13　%,　with　almost　all　of　the　sulfur　existing　in　the　form　of　thiophene　compounds.　The　introduction　of　H2　and　the　addition　of　Na2CO3　both　promote　the　sulfur　release　of　HSPC　at　800　degrees　C.　With　a　50　%　addition　of　Na2CO3　and　the　introduction　of　H2,　87.2　%　of　the　sulfur　is　released　from　the　HSPC.　The　details　of　sulfur　distribution　during　the　desulfurization　reaction　were　determined　to　clarify　the　roles　of　H2　and　Na2CO3.　Thiophene　is　mainly　transformed　into　gaseous　and　water-soluble　sulfur　compounds.　The　gaseous　sulfur　includes　H2S,　elemental　sulfur,　and　sulfur-containing　tar　(Tar-S).　The　water-soluble　sulfur　compounds　are　primarily　sulfides　and　sulfates　adsorbed　on　the　petroleum　coke,　which　can　be　removed　by　water　washing.　The　results　show　that　H2　and　the　addition　of　Na2CO3　exhibit　a　synergistic　effect　on　HSPC　desulfurization.　H2　promotes　the　hydrogenolysis　of　C-C　and　C-S　bonds　in　benzothiophene　to　form　H2S　and　Tar-S,　while　Na2CO3　acts　as　a　captor　of　sulfurcontaining　compounds.　The　findings　of　this　work　provide　a　foundation　for　the　development　of　a　cost-effective　and　highly　efficient　industrial　desulfurization　process.