The nanometer TiO2 film is achieved by sol-gel method, and using tetrabutyl titanate as source, ethanol as solvent, acetic acid as complexing agent. The nanometer TiO2 film is prepared by using spin coating method. Methylene blue solution is degraded by the nanometer TiO2 film. The photocatalytic degradation efficiency is influenced by the nanometer TiO2 film amount, irradiation time, the UV irradiation intensity and solution temperature. The short degradation time shows that the nanometer TiO2 film can be used as an easy and efficient method to degrade methylene blue solution.