Two-dimensional MXene is a precursor, an ordered nanosheet structure is constructed and a uniform carbon layer is modified, and a highly visible light active TiO2 photocatalyst is prepared. Under visible light conditions, the photocatalytic activity of TiO2 nanosheets / C composites has increased threefold compared to TiO2. The results show that the high photocatalytic activity can be attributed to three reasons. One is the ordered nanosheet structure inherited from the two-dimensional MXene, which is conducive to the hole separation and transportation of electrons. Secondly, the modification of the carbon layer will obviously expand more visible light absorption regions. In addition, the carbon layer also promotes the separation and migration of photogenerated carriers. The proposed in-situ carbon modification strategy enhances the visible light photocatalytic activity and develops a photocatalytic mechanism.