Pt and Cr codoped NanoTiO2 film was prepared by the solgel method. The film was characterized by AFM, XRD and UVVis. The experiment showed that when the average TiO2 film diameter is 32 nm and the film thickness is 290 nm, the rate of photodegradation is 95% in 2.5 hours. Additionally, when the optimal codoping ratio for PtCr is n(Pt): n(TiO2) equals 0.03% and n(Cr):n(TiO2) equals 0.4%, the photodegradation of methylene blue for NanoTiO2 film can be enhanced. The photocatalytic properties of Pt and Cr codoped NanoTiO2 film is better than that of pure TiO2 and Pt, Cr separatelydoped TiO2 film.