Constructing　heterojunctions　with　transition　metal　sulfides　is　an　excellent　strategy　to　reduce　the　dependency　on　noble　metals　in　photocatalytic　water　splitting.　Herein,　0D　CoMoS4　nanoparticles　were　first　deposited　in-situ　on　the　surface　of　3D　ZnIn2S4　microflowers　for　constructing　heterostructured　CoMoS4–ZnIn2S4　(CMS-ZIS)　composites.　The　CMS-ZIS　composites　showed　strengthened　absorption　capabilities　in　the　visible　light　region　compared　with　pure　ZnIn2S4.　The　electron　microscopy　scanning　images　indicate　that　countless　CoMoS4　particles　were　loaded　into　the　gaps　on　the　surface　of　ZnIn2S4　microflowers,　resulting　in　a　close　interface　contact　between　the　materials.　The　photocatalytic　hydrogen　evolution　(PHE)　rate　of　the　optimized　CMS-ZIS-3　product　is　6.43　folds　that　of　pure　ZnIn2S4,　which　is　approximately　3942.1　μmol　g−1　h−1.　The　enhanced　activity　should　be　attributed　to　the　promoted　carrier　transfer　rate　and　reduced　recombination　efficiency.　We　inferred　the　possible　mechanism　for　photocatalytic　hydrogen　production　over　CMS-ZIS-3　based　on　the　band　potential　and　photoelectrochemical　testing　results.　This　study　provides　a　feasible　strategy　for　designing　efficient　and　cost-effective　0D/3D　heterostructures.　©　2023　Elsevier　Masson　SAS