Abstract: TiO₂/nanocrystalline cellulose composite solution was prepared via blending nano TiO₂ powder and nanocrystalline cellulose solution, which was produced by dissolving microcrystalline cellulose(MCC) in low temperature NaOH-ureal aqueous solution, and then regeneration in water bath. The composite solution was coated on glass to form TiO₂/nanocrystalline cellulose composite film by adding a little tetrabutyl orthotitanate as cross-linking agent. The morphology and structure of the composite films were characterized by using SEM and XRD. The photocatalytic activitives of the composite films were evaluated by decomposition of the methyl orange under UV-light irradiation. The mass fraction of the TiO₂ in the film, and the repeatability of photocatalytic activity of the films were discussed, and also the degradation kinetics was analyzed. The results show that photocatalytic activity of the films is comparable to the pure TiO₂ powder, up to 90%.When the films are repeated three times, it still keeps the same photocatalytic activity. The dynamic kinetics of the photodegradation is first order process. When the mass fraction of TiO₂ is up to 33.3%, the film possesses the better photocatalytic activity and higher dynamic rate constant with 0.035 min^-1.