Abstract: TiO₂ film was prepared on JGS1 quartz substrate by the sol-gel method. The relation between the crystal structure and photocatalysis performance of TiO₂ film and the photocatalysis effect of TiO₂ film on silicone oil with macromolecular chain under ultraviolet radiation are studied. The results show that after 500 ℃ heat treatment, the TiO₂ film with anatase structure shows superior photocatalysis activity. The photodegradation of TiO₂ film on silicone oil under 250 nm UV radiation is significant. The study may be helpful in developing anti-contamination materials on the optical surface in spacecraft under space environment.