Using　ab　initio　method,　the　electronic　structures　of　the　clusters　containing　the　cis(　I　)/　trans(　I　＇)-Mo2S4　and　Mo2O4(　II　)　core　have　been　studied.　The　(4s4p2d)　pseudopotential　basis　set　of　Mo　atom　has　been　chosen　for　the　calculations　of　the　dinuclear　molybdenum　clusters　by　optimizing　the　geometry　of　cluster(　I),　The　chemical　bondings　of　three　clusters　are　discussed　by　using　the　natural　bond　orbital　(NBO)　method　and　comparing　with　the　similar　dinuclear　tungsten　clusters.　The　IR　vibration　frequencies　of　three　clusters　have　been　calculated,　the　main　absorption　bands　are　assigned　and　compared　with　each　other.　The　electronic　spectra　have　been　calculated　using　the　CIS　method,　it　is　shown　that　the　lowest　excited　states　of　three　clusters　are　the　result　from　two　transitions,　sigma((Mo-Mo))--＞pi((Mo-xt))*　(X　=　S,O)　and　sigma((Mo-Mo))--＞M(Mo-Mo)*,　and　the　contribution　of　the　former　are　greater.