A　novel　strategy　was　developed　to　fabricate　a　CdS/Pt　photocatalyst　(defined　as　CdS/w%Pt-PAR)viathe　cathodic　photocorrosion　effect　of　CdS.　A　tentative　mechanism　for　Pt　deposition　on　CdSviathe　cathodic　photocorrosion　effect　was　proposed,　based　on　a　series　of　electrochemical　characterization　methods,　such　as　cyclic　voltammetry　and　Mott-Schottky　tests.　Transmission　electron　microscopy　verified　that　Pt　was　grafted　on　the　CdS　surfaceviaa　heterojunction.　Moreover,　a　strong　interaction　between　Pt　and　CdS　was　further　confirmed　by　X-ray　photoelectron　spectroscopy.　The　optimal　photocatalytic　H2evolution　rate　of　CdS/2%Pt-PAR　was　1086.1　μmol　h−1,　6.4　and　2.6　fold　higher　than　that　of　the　reference　samples　synthesized　by　traditional　photodeposition　(CdS/2%Pt-PD)　and　chemical　reduction　(CdS/2%Pt-CR)　methods,　respectively.　Linear　sweep　voltammetry　and　fluorescence　experiments　verified　that　CdS/2%Pt-PAR　has　a　lower　H2evolution　overpotential　and　faster　separation　of　photogenerated　carriers,　respectively,　compared　with　CdS/2%Pt-PD　and　CdS/2%Pt-CR.　This　work　paves　a　new　route　for　fabricating　CdS/metal　photocatalysts　with　highly　efficient　and　stable　photocatalytic　H2evolution　activity.　©　The　Royal　Society　of　Chemistry　and　the　Centre　National　de　la　Recherche　Scientifique　2021.