Titanium dioxide (TiO2) is regarded as the best known semiconductor photocatalysts, but its large band gap and low rate of photogenerated charge separation impede the application to solve the environmental contaminations and energy crisis. Reducing band gap and improving electron-hole separation and migration have remained a longstanding challenge. While creating the junctions between different crystal phases and substance is an effective method. In this work, we prepared the V2O5/rutile-anatase photocatalyst system with homo-hetero junctions via a facile incipient wet impregnation method. In this system, the synergetic effects of homo-and hetero-junctions are beneficial to separate the generated electron-hole pairs, facilitate interfacial charge-transfer rate, and reduce band gap, which greatly promote photocatalytic activities. Furthermore, it exhibits an enhanced activity on photocatalytic oxidation of elemental mercury (Hg-0), which shows the highest Hg-0 oxidation efficiency of 93.58% under visible light. The result suggests that combination of both homo-and hetero-junctions in one photocatalyst is a promising method to improve the photocatalytic activities for solving the environmental contaminations and energy crisis. We believe that the preparation of this new photocatalyst system may be a great assist in the design and preparation of efficient photocatalyst. Meanwhile, this method is sought-after for large-scale industrial applications of photocatalysis.