In this study, the natural vanadiferous and ferruginous rutile was modified by heat treatment with the temperatures ranging from 500～1000℃ under the condition of argon atmosphere. XRD patterns of treated samples have revealed that there exist different levels of cell expansion with the increasing temperature, and a new phase, ilmenite, is formed above 900℃. The UV_vis diffuse reflection spectra show that the visible absorption is distinctly improved after argon heat treatment. Compared with the previous modification under air atmosphere, the heat treatment under argon atmosphere proves to be more efficient in raising the visible light response.