A　series　of　dehydrated　MoS2/UiO-66(SH)(2)　(MS/UiS)　composites　has　been　prepared　as　photocatalysts　for　N-2　fixation.　Typically,　10%　MS/UiS　exhibits　the　best　performance　with　an　NH4+　yield　rate　of　54.08　mu　mol　center　dot　g(-1)center　dot　h(-1).　N-15　isotope　test　confirmed　that　the　sample　10%　MS/UiS　was　most　effective　for　reducing　N-2　to　ammonia.　Such　enhanced　activity　was　due　to　the　presence　of　abundant　unsaturated　Zr　and　Mo　sites　which　would　synergistically　promote　the　adsorption　and　activation　of　N-2.　The　photogenerated　electrons　would　transfer　to　the　unsaturated　ZrO　clusters　while　part　of　photogenerated　electrons　at　the　interface　migrate　to　MS　via　Mo-VI-O　interactions　between　MS　and　UiS.　These　two　electron　transfer　pathways　effectively　promote　the　separation　of　photogenerated　carriers.　The　activated　N-2　is　reduced　to　ammonia　by　the　synergistic　effect　of　protonated　hydrogen　and　photogenerated　electrons.　Finally,　a　possible　N(2　)fixation　mechanism　is　proposed　which　emphasizes　the　significant　roles　of　nitrogen　activation　and　interface　interaction　in　composites　photocatalyst　for　improving　photocatalytic　performance.