The pure ZnS can not absorb visible light because of its large band gap of 3.6 eV. The ZnO/ZnS was obtained from partial oxidation of ZnS, and its band gap was 2.5 eV where visible light can be absorbed. From XRD analysis, it was confirmed that only ZnO was formed during oxidation process but not ZnSO₄. In case of ZnO/ZnS, the quantum efficiency for the hydrogen evolution from water was 0.87% under visible light irradiation. In order to improve the interaction between ZnO and ZnS, ZnS/ZnO was prepared by precipitating ZnS on ZnO. After calcination of ZnS/ZnO, the band gap became narrow. The pure ZnO and the physically mixed ZnS-ZnO could not absorb visible light, but the ZnS-doped ZnO (ZnS/ZnO) could do. The band gap of pure ZnO was 3.2 eV and that of ZnS/ZnO was 2.5 eV. The best activity was obtained when calcination temperature and time were 500 ℃ and 1 h, respectively. The quantum efficiency of ZnS/ZnO for the reaction was 3.29%.