As an efficient cocatalyst, the 2D MoS2 is thought to be a promising substitute to noble metals in the hydrogen evolution reaction (HER). In the past few years, single and few-layer MoS2 nanosheets have attracted a wide range of concerns for HERs. In this paper, single crystalline ZnO nanowires and MoS2 nanosheets are fabricated to form MoS2 nanosheet/ZnO nanowire hybrid nanostructure to enhance the hydrogen photogeneration. The results show that the hybridization of ZnO with moderate MoS2 loading could enhance the PEC activity by producing more electrons and holes and reducing their recombination. The synthesis of MoS2/ZnO composites proposed an effective way to build low cost and highly active HER catalysts. Moreover, the study on MoS2/ZnO composites sheds light to the deep insight into the mechanism of photoelectrocatalytic HERs.