A novel photodegradable polyethylene-oxidized polyethylene wax-TiO2 (PE-OPW-TiO2) nanocomposite film was prepared by embedding the organically modified TiO2 nanoparticles into commercial PE in the presence of OPW. The photocatalytic degradation behavior under ultraviolet light or solar light was investigated by examining the weight loss of the composite films, UV-vis transmittance spectrum, scanning electron microscope (SEM), and gel permeation chromatogram (GPC). The results show that OPW, as a dispersant and a compatibiliser, markedly improves the dispersion and compatibility of TiO2 nanoparticles in PE resins. The PE-OPW-TiO2 composite film demonstrates much higher photodegradation efficiency and much better mechanical property than either the PE-TiO2 composite film or the pure PE film. The weight-average molecular weight (M,) of the PE-OPW-TiO2 composite film decreased 94.3% and the number-average molecular weight (M-n) decreased 84.5% after 38 days solar light irradiation. The photocatalytic degradation mechanism of the film is briefly discussed. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 378-384, 2010