The　active　center　for　the　adsorption　and　activation　of　carbon　dioxide　plays　a　vital　role　in　the　conversion　and　product　selectivity　of　photocatalytic　CO2　reduction.　Here,　we　find　multiple　metal　sulfides　CuInSnS4　octahedral　nanocrystal　with　exposed　(1　1　1)　plane　for　the　selectively　photocatalytic　CO2　reduction　to　methane.　Still,　the　product　is　switched　to　carbon　monoxide　on　the　corresponding　individual　metal　sulfides　In2S3,　SnS2,　and　Cu2S.　Unlike　the　common　metal　or　defects　as　active　sites,　the　non-metal　sulfur　atom　in　CuInSnS4　is　revealed　to　be　the　adsorption　center　for　responding　to　the　selectivity　of　CH4　products.　The　carbon　atom　of　CO2　adsorbed　on　the　electron-poor　sulfur　atom　of　CuInSnS4　is　favorable　for　stabilizing　the　intermediates　and　thus　promotes　the　conversion　of　CO2　to　CH4.　Both　the　activity　and　selectivity　of　CH4　products　over　the　pristine　CuInSnS4　nanocrystal　can　be　further　improved　by　the　modification　of　with　various　co-catalysts　to　enhance　the　separation　of　the　photogenerated　charge　carrier.　This　work　provides　a　non-metal　active　site　to　determine　the　conversion　and　selectivity　of　photocatalytic　CO2　reduction.