Transparent ZnO sols have been prepared by sol-gel method and deposited on aluminum foil substrates by dip-coating method, and then calcinated at 500℃ to obtain visible-light response nano-sized ZnO film photocatalysts. The films have been applied in photocatalytic degradation of methyl orange as model of organic pollutant under visible-light irradiation. The results show that the degradation of methyl orange reaches 96.3% by using a piece of ZnO/Al thin film as photocatalyst with an efficient irradiation area of 200 cm^2, which is higher than that of ZnO/glass film. The films have been characterized by means of scanning electron microscopy and atomic force microscope, which indicated that photocatalytic activity of porous ZnO films should be higher than that of compact cumulate ZnO films; and the ZnO/Al film with high visible light response is formed by a layer of ZnO nano-sized particles with average diameter of 52.2 nm. The results suggest that the ZnO-supported commercial aluminum foil is a promising and efficient thin film catalyst to degrade organic pollutants under visible light irradiation.