Undoped TiO2 and Cu-doped TiO2 (Cu-TiO2) nano-structured thin films were prepared by a sol-gel process on glass substrates. We investigated their structures, surface morphologies, and tribological properties by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), X-ray diffraction (XRD), and friction and wear testing using a UMT-3 tester. We found that the prepared Cu-TiO2 films were smoother and more uniform than the undoped TiO2 films and they had better friction-reducing and anti-wear properties. The amount of Cu dopant directly affects the tribological performance of the doped TiO2 film. The 5%(mole fraction) Cu-TiO2 film possesses the longest wear life and the lowest friction coefficient.