The　catalytic　activity　for　the　hydrogen　evolution　reaction　(HER),　as　well　as　the　structural　and　electronic　properties,　of　monolayer　MoS2　with　single　Mo　vacancies　(VMo-SLMoS2)　under　different　strains　were　investigated　by　first-principles　density　functional　theory　(DFT)　for　the　first　time.　We　found　that　the　HER　catalytic　activity　of　VMo-SLMoS2　can　be　optimized　using　biaxial　compressive　strain.　A　4.5%　biaxial　compressive　strain　can　be　used　to　reduce　ΔGH　to　be　only　-0.03　eV　and　-0.04　eV　at　the　active　sites.　Our　results　suggest　a　new　way　for　the　applications　of　SLMoS2　in　the　optimization　of　hydrogen　evolution　performance　with　point　defects.　©　2019　IEEE.