Molybdenum　disulfide　(MoS2)　has　been　demonstrated　as　a　promising　non-precious　metal　electrocatalyst　for　the　hydrogen　evolution　reaction　(HER).　However　the　efficiency　of　the　HER　falls　short　of　expectations　due　to　the　large　inert　basal　plane　and　poor　electrical　conductivity.　In　order　to　activate　the　MoS2　basal　plane　and　enhance　the　hydrogen　evolution　reaction　(HER)　activity,　two　strategies　on　the　hybrid　MoS2/graphene,　including　intrinsic　defects　and　simultaneous　strain　engineering,　have　been　systematically　investigated　based　on　density　functional　theory　calculations.　We　firstly　investigated　the　HER　activity　of　a　MoS2/graphene　hybrid　material　with　seven　types　of　point　defect　sites,　VS,　VS2,　VMo,　VMoS3,　VMoS6,　MoS2　and　S2Mo.　Using　the　hydrogen　adsorption　free　energy　(?GH)　as　the　descriptor,　results　demonstrate　that　four　of　these　seven　defects　(VS,　VS2,　MoS2,　VMoS3)　act　as　a　catalytic　active　site　for　the　HER　and　exhibited　superior　electrocatalytic　activity.　More　importantly,　we　found　that　?GH　can　be　further　tuned　to　an　ideal　value　(0　eV)　with　proper　tensile　strain,　which　effectively　optimizes　and　boosts　the　HER　activity,　especially　for　the　VS,　VS2,　VMoS3　defects　and　MoS2　antisite　defects.　Our　results　demonstrated　that　a　proper　combination　of　tensile　strain　and　defect　structure　is　an　effective　approach　to　achieve　more　catalytic　active　sites　and　further　tune　and　boost　the　intrinsic　activity　of　the　active　sites　for　HER　performance.　Furthermore,　the　emendatory　d-band　center　of　metal　proves　to　be　an　excellent　descriptor　for　determining　H　adsorption　strength　on　defective　MoS2/graphene　hybrid　material　under　different　strain　conditions.　In　addition,　the　low　kinetic　barrier　of　H2　evolution　indicated　that　the　defective　MoS2/graphene　system　exhibited　favorable　kinetic　activity　in　both　the　Volmer-Heyrovsky　and　the　Volmer-Tafel　mechanism.　These　results　may　pave　a　new　way　to　design　novel　ultrahigh-performance　MoS2-based　HER　catalysts.　©　2023　The　Royal　Society　of　Chemistry.