Cd1−xZnxS　solid　solutions　with　strong　light　absorption　are　promising　materials　for　solar-driven　CO2　reduction;　however,　their　relatively　weak　redox　ability　and　intrinsic　photo-corrosion　limit　their　further　development　as　a　photocatalyst.　The　addition　of　a　second　photocatalyst　with　a　suitable　band　structure　to　construct　a　S-scheme　photocatalytic　system　can　solve　both　problems　simultaneously.　Here,　we　report　a　S-scheme　photocatalyst　based　on　the　heterostructure　of　CoTiO3/Cd9.51Zn0.49S10　(abbreviated　as　CoTiO3/CdZnS)　that　enables　the　efficient　photocatalytic　reduction　of　CO2.　Detailed　physicochemical　characterization　resolves　the　S-scheme　charge　transfer　mechanism　in　this　composite　photocatalyst.　With　the　well-designed　structure　of　particles　and　desirable　band　offsets,　this　hybrid　system　offers　visible　light　absorption　in　a　broad　spectral　region,　large　surface　area,　strong　redox　ability,　and　fast　carrier　separation　and　transportation.　Under　visible-light　illumination,　the　CoTiO3/CdZnS　hybrid　system　displays　a　CO　formation　rate　of　about　11　mmol　h−1　g−1　combined　with　a　long-term　operational　stability.　Besides,　a　high　apparent　quantum　efficiency　(AQE)　of　7.27%　is　realized　for　the　CO2-to-CO　reduction　reaction　by　the　optimized　CoTiO3/CdZnS　hybrid　under　420　nm　monochromatic　light　irradiation.　©　2022