Pt　clusters　supported　on　monolayer　Bi2MoO6　nanosheets　(Pt/BMO-NS)　are　constructed　for　the　photocatalytic　selective　reduction　of　4-nitrostyrene　to　4-vinylaniline　in　the　presence　of　HCOONH4　and　exhibit　high　conversion　(approximate　to　100%)　of　4-nitrostyrene　and　high　selectivity　(approximate　to　100%)　of　4-vinylaniline.　In　situ　FTIR　spectra　and　XPS　spectra　of　BMO-NS　absorbed　4-nitrostyrene　further　demonstrate　that　4-nitrostyrene　can　be　selectively　absorbed　and　activated　on　surface　Mo5+　and　Bi2+　sites　of　BMO-NS　via　the　Bi　center　dot　center　dot　center　dot　O-N　or　Mo　center　dot　center　dot　center　dot　O-N　coordination.　The　Pt　clusters　and　photogenerated　carriers　synergistically　make　the　efficient　dissociation　of　HCOO-　to　form　rich　center　dot　CO2-　and　active　center　dot　H,　greatly　supporting　the　selective　reduction　of　4-nitrostyrene　to　4-vinyaniline.　This　work　not　only　highlights　the　complete　utilization　of　photo-generated　carriers　to　achieve　the　selective　reduction　of　4-nitrostyrene　to　4-vinylaniline　via　photocatalytic　hydrogen　transfer,　but　also　uses　metal/monolayer　nanosheets　as　a　molecule　platform　to　deeply　study　the　surface/interface　synergetic　mechanism　at　the　molecule　level.