Abstract: Nano- TiO₂ / regenerated cellulose films with different titania content s were prepared by directly blendingtitania powder and cellulose (pulp) in 1-allyl-3-methylimidazolium chloride ionic liquid at room temperature. Thecellulose was regenerated by water and then dried by supercritical CO₂ . The morphology , phase component s , st ructure and thermal property of the films were characterized by SEM , XRD and FTIR. The photocatalytic activities ofthe films were evaluated for decomposition of the methylene blue under UV light irradiation by PCC-2 photocatalysisevaluation checker. The influencing factors on photocatalytic activity of the films were discussed , such as the content of nano-TiO₂ and the drying methods of supercritical CO₂ . The result s show that , with the addition of titania ,the photocatalytic activity of the films t reated by supercritical CO₂ medium is higher than that of films dried in vacuum. The photocatalytic activity of the films increases with the increasing of nano- TiO₂ particles up to 5 % and thendecreases with the increasing of TiO₂ content .