Amorphous MoSx cocatalyst was loaded on CdS NRs by a simple photodeposition. MoSx/CdS NRs exhibited 6 times higher hydrogen evolution efficiency than Pt/CdS NRs. The hydrogen evolution of MoSx/CdS NRs linearly increased with prolonging time. Lower overpotential and efficient electron transfer were observed over MoSx/CdS NRs.