As a kind of photocatalytic semiconductor material, natural sphalerite has a considerable photocatalytic capability in visible light. However, its structural defects could be the capture trap of photo-generated electrons, which results in the decrease of its photocatalytic reaction efficiency. To further improve its photocatalytic efficiency in visible light, the authors conducted the heat-treating experimental study of natural sphalerite at 500～1 200℃ in static air. The physical and chemical semiconductor properties of the original and modified samples were analyzed and characterized by using testing means of X-ray Diffraction (XRD) and UV-Vis Diffuse Reflectance Spectra (UV-Vis DRS). Then the photocatalytic experimental study which utilized the original and modified samples to degrade methyl orange was performed. The X-ray diffraction results showed that sphalerite was converted into Zn₃O(SO₄)₂ and then into zincite and franklinite with the increasing heat-treating temperature. Samples were totally converted into ZnO-ZnFe₂O₄ binary compound semiconductor at 1 100～1 200℃. The UV-Vis Diffuse Reflectance Spectra results show that the response of modified samples to visible light is stronger than that of the original sample, and the absorption range of visible light of 900～1 200℃ modified samples is larger than that of 500～800℃ modified samples. The degradation experimental results show that the 1 100～1 200℃ heat-modification of natural sphalerite significantly improved its degradation rate of methyl orange from 54.2% to 99.7%, which indicates that the photocatalytic capability in visible light of 1 100～1 200℃ modified samples is the best. Based on these test and experimental results, the authors infer that the photocatalytic capability in visible light of ZnO-ZnFe₂O₄ binary compound semiconductor is higher than that of the single ZnS semiconductor and other types of compound semiconductor.