Constructing　novel　surface　microstructures　for　photocatalytic　materials　could　significantly　enhance　the　photocatalytic　hydrogen　production　rate　from　water　splitting.　In　this　work,　novel　2D/3D　structured　CuCo2S4/CdIn2S4　p-n　heterojunction　photocatalysts　for　water　splitting　were　successfully　prepared　by　a　solvothermal　method.　The　coupling　of　a　2D　CuCo2S4　nanoplate　on　the　surface　of　3D　flower-like　CdIn2S4　microspheres　has　strengthened　the　visible　light　absorption　and　promoted　the　charge　separation　efficiency　due　to　their　tight　contacting　area.　The　obtained　CuCo2S4/CdIn2S4　(CSCIS-2)　photocatalyst　exhibited　a　hydrogen　production　rate　of　1320　μmol　g-1　h-1,　which　was　fivefold　of　that　for　pure　CdIn2S4.　Additionally,　cyclic　tests　demonstrated　improved　photoactivity　stability　of　the　samples.　A　series　of　photoelectrochemical　characterizations　confirmed　the　effective　suppression　of　charge　carrier　recombination　in　CuCo2S4/CdIn2S4　composite　catalysts.　Finally,　a　rational　photocatalytic　mechanism　was　proposed　based　on　the　semiconductor　band　theory.　This　work　contributes　to　the　enrichment　of　sulfide-based　research　and　applications　in　photocatalysis.　©　2024　American　Chemical　Society.