p-Si　nanowire　(Si-NW)　arrays　are　successfully　decorated　with　molybdenum–sulfur　(MS)　clusters　by　a　drop-casting　method.　The　composited　photocathode　(MS/Si-NW)　demonstrated　an　enhanced　photoelectrochemical　(PEC)　hydrogen　production　performance,　with　a　photocurrent　density　of　−14.3 mA/cm2　at　a　potential　of　0 V　vs.　RHE　under　the　illumination　of　the　red　part　of　simulated　solar　light　(λ > 590 nm,　27.3 mW/cm2).　The　photocathode　also　showed　a　good　stability　in　the　long-term　photocatalytic　hydrogen　evolution　measurement,　and　the　Faradaic　efficiency　of　hydrogen　production　was　close　to　100%.　Additionally,　the　morphological,　optical　and　wetting　properties　of　the　photoelectrodes　were　investigated　in　detail.　On　the　basis　of　the　results,　it　could　be　concluded　that　the　enhanced　PEC　performance　is　attributed　to　the　high　surface　area,　low　light　reflection　and　good　wetting　property　of　Si-NW,　together　with　a　low　overpotential　for　hydrogen　evolution　reaction　(HER)　of　the　molybdenum–sulfur　clusters.　©　2016　Hydrogen　Energy　Publications　LLC