Photocatalytic　reduction　of　carbon　dioxide　can　convert　chemically　inert　carbon　dioxide　into　useful　chemical　fuel　in　a　mild　manner.　Herein,　Ag-CdS　nanocomposites　were　prepared　by　photodeposition　method　and　examined　for　photocatalytic　CO　2　reduction　under　visible　light.　Meanwhile,　the　nanocomposites　were　characterized　by　XRD,　SEM,　TEM,　XPS,　DRS　and　PL　in　detail.　The　results　show　that,　the　deposition　of　Ag　improves　the　photocatalytic　performance　of　CdS,　especially　in　the　selectivity　of　CO　2　-to-CO.　The　highest　photocatalytic　activity　is　achieved　over　1.0 wt.%　Ag/CdS,　with　an　increase　by　3　times　in　comparison　to　CdS.　In　this　reaction　system,　Ag　can　serve　as　electron　trap　as　well　as　active　site　for　CO　2　reduction,　which　is　probably　responsible　for　the　enhanced　activity　and　selectivity　of　CO　2　to　CO　over　Ag/CdS.　The　possible　mechanism　of　CO　2　photoreduction　over　Ag/CdS　was　proposed　in　view　of　the　abovementioned　analysis.　©　2016　Elsevier　B.V.