Exploring　high-efficiency　Z-scheme　heterojunction　photocatalyst　has　been　regarded　as　an　effective　approach　for　promoting　photocatalytic　hydrogen　production　efficiency.　In　this　study,　a　novel　direct　Z-scheme　heterojunction　composed　of　AgIn5S8　(denoted　as　AIS)　and　Zn-defective　ZnS　(denoted　as　D-ZnS)　was　fabricated　via　two-step　hydrothermal　method.　The　AIS/D-ZnS　heterojunction　exhibited　improved　visible　light　harvesting　capability,　prolonged　charge　lifetime　and　promoted　charge　separation　efficiency,　thus　contributing　to　the　remarkably　enhanced　photocatalytic　activity　as　well　as　stability.　The　photocatalytic　H2　evolution　rate　of　the　optimized　(0.10:1)AIS/D-ZnS　reached　932.76　mu　mol.h(-1)　g(-1),　which　was　12　times　higher　than　that　of　bare　D-ZnS　(75.13　[mu　mol.h(-1)　g(-1))　under　visible　light　irradiation,　and　an　optimal　apparent　quantum　yield　of　3.7%　was　achieved　at　lambda　=　420　nm.　TEM,　XPS,　EPR　and　PL　results　confirmed　the　appropriate　concentration　of　Zn　defects　is　conducive　to　the　separation　of　photogenerated　carriers.　DMPO-EPR　and　PL　probe　experiments　for　determining　O-center　dot(2)-　and　(OH)-O-center　dot　active　radicals　further　proved　that　the　transfer　and　separation　of　electrons　and　holes　followed　Z-scheme　mechanism.　This　work　not　only　presents　an　alternative　strategy　for　the　construction　of　highly　efficient　Z-scheme　heterojunction　photocatalysts,　but　also　provides　new　insights　into　the　role　of　defects　in　mediating　the　separation　and　migration　of　charge　carriers.