Effective　charge　separation　and　migration　pose　a　critical　challenge　in　the　field　of　solar-driven　hydrogen　production.　In　this　work,　a　Z-scheme　structured　CuInS2/ZnIn2S4　heterojunction　was　successfully　fabricated　through　a　two-step　hydrothermal　synthesis　method　to　significantly　enhance　the　efficiency　of　solar-to-hydrogen　energy　conversion.　Structural　characterization　revealed　that　the　lattice-matched　CuInS2/ZnIn2S4　heterojunction　exhibits　an　enlarged　interfacial　contact　area,　which　facilitates　the　transfer　and　separation　of　photogenerated　charges.　Microscopic　analysis　indicated　that　the　CuInS2/ZnIn2S4　composite　material　has　a　tightly　interwoven　interface　and　a　morphology　resembling　small　sugar　cubes.　Photoelectrochemical　spectroscopy　analysis　demonstrated　that　the　heterojunction　structure　effectively　enhances　visible　light　absorption　and　charge　separation　efficiency,　leading　to　an　improvement　in　photocatalytic　activity.　Hydrogen　production　experimental　data　indicated　that　the　CuInS2/ZnIn2S4　heterojunction　photocatalyst　prepared　with　a　CuInS2　content　of　20　wt%　exhibits　the　highest　hydrogen　evolution　rate,　reaching　284.9　μmol·g−1·h−1.　Moreover,　this　photocatalyst　maintains　robust　photocatalytic　stability　even　after　three　consecutive　usage　cycles.　This　study　demonstrated　that　the　Z-scheme　CuInS2/ZnIn2S4　heterojunction　photocatalyst　exhibits　enhanced　hydrogen　evolution　efficiency,　offering　an　effective　structural　design　for　harnessing　solar　energy　to　obtain　hydrogen　fuel.　Therefore,　this　heterojunction　photocatalyst　is　a　promising　candidate　for　practical　applications　in　solar　hydrogen　production.　©　2024　by　the　authors.