Transition-metal　chalcogenide　quantum　dots　(TMCs　QDs)　exhibit　emerging　potential　in　the　field　of　solar　energy　conversion　due　to　large　absorption　coefficients　for　light　harvesting,　quantum　size　effect,　and　abundant　active　sites.　However,　fine-tuning　the　photoinduced　charge　carrier　over　TMCs　QDs　to　manipulate　the　directional　charge-transfer　pathway　remains　challenging,　considering　their　ultrashort　charge　lifetime　and　slow　charge-transfer　kinetics.　To　this　end,　herein,　MoSx/PDDA/TMCs　QDs　heterostructures　were　exquisitely　designed　by　a　simple　and　green　electrostatic　self-assembly　strategy　under　ambient　conditions,　wherein　tailor-made　negatively　charged　TMCs　QDs　stabilized　by　mercaptoacetic　acid　(MAA)　were　precisely　self-assembled　on　the　positively　charged　polydiallyl　dimethylammonium　chloride　(PDDA)-modified　MoSx　nanoflowers　(NFs),　forming　a　well-defined　three-dimensional　heterostructured　nanoarchitecture.　As　an　electron　trapping　agent,　an　MoSx　NFs　cocatalyst　benefits　the　unidirectional　electron　transfer　from　TMCs　QDs　to　the　ideal　active　centers　on　the　MoSx　NFs　surface　by　tunneling　the　ultrathin　insulating　polymer　interim　layer,　thereby　boosting　the　charge　separation　efficiency　and　endowing　self-assembled　MoSx/PDDA/TMCs　QDs　heterostructures　with　considerably　increased　photocatalytic　hydrogen　evolution　activity　(1.96　mmol·g-1·h-1)　and　admirable　stability　under　visible　light　irradiation.　Our　work　will　provide　new　insights　into　smart　regulation　of　directional　charge　transfer　over　TMCs　QDs-based　photosystems　for　solar　energy　conversion.　©　2023　American　Chemical　Society.