In this study, based on the sol-gel spin coating method, aluminum and nitrogen co-doped TiO₂ film samples were prepared with aluminum doping amount of 3.00at%, and nitrogen doping amount of 6.00at%, 7.00at%, 8.00at%, and 9.00at%, respectively. The test results of the samples show that the basic structure of TiO₂ is still retained in the co-doped samples, and the grain size of aluminum and nitrogen co-doped samples is reduced to different degrees, which makes the surface of the samples modified to become more uniform and flat compared with that of the undoped. The co-doped samples showed different degrees of red shift and enhanced absorbance in both UV and visible regions. When the doping amount of nitrogen is 7.00at%, the diffraction peak of (101) is the largest, the peak type is the sharpiest, and the obtained TiO₂ film has the best optical performance. Compared with the eigenstate TiO₂, the band gap values of the co-doped samples are decreased, and the minimum value is 2.873eV. The above results indicate that Al/N co-doped TiO₂ film can improve its optical properties.