Density　functional　theory　(DFT)　and　coupled　cluster　theory　(CCSD(T))　calculations　were　employed　to　investigate　the　geometric　and　electronic　structures　of　a　range　of　dinuclear　molybdenum　sulfide　clusters,　Mo2Sn　–　and　Mo2Sn　(n　=　4~8).　The　results　showed　that　the　sulfur　atoms　tended　to　occupy　the　terminal　sites　of　the　clusters　continuously　in　the　process　of　sequential　sulfidation.　After　the　oxidation　state　of　Mo　atoms　reached　the　maximum　of　+6,　diverse　disulfur　ligands　emerged　in　the　sulfur-rich　Mo2Sn　–/0　(n　=　7,　8)　clusters.　The　driving　forces　of　removing　a　sulfur　atom　from　different　S　ligands　in　Mo2Sn　–/0　(n　=　4~8)　clusters,　especially　from　those　disulfur　units,　were　evaluated.　The　corresponding　order　may　provide　insight　into　the　pretreatment　of　fresh　MoS2　catalysts.　Vertical　detachment　energies　(VDEs)　were　predicted　according　to　the　Generalized　Koopmans’　theorem,　and　then　the　photoelectron　spectra　(PES)　were　simulated.　Molecular　orbital　and　spin　density　values　were　analyzed　to　elucidate　the　chemical　bonding　and　the　evolutionary　behavior　in　the　dinuclear　molybdenum　sulfide　clusters.　©　2018　Fujian　Institute　of　Research　of　the　Structure　of　Matter.　All　rights　reserved.