A novel photodegradable poly(vinyl chloride)-polyoxometalate/TiO2 (PVC-POM/TiO2) nanocomposite film was prepared by embedding nano-TiO2 photocatalyst modified by POM into the commercial PVC plastic. The solid-phase photocatalytic degradation behavior of as-prepared film under UV light irradiation was investigated and compared with those of the PVC-TiO2 film and the pure PVC film, with the aid of FTIR spectroscopy, scanning electron microscopy (SEM), and weight loss monitoring. The results show that PVC-POM/TiO2 nanocomposite film has a high photocatalytic activity. The optimal ratio of POM to TiO2 is found to be 2 wt %, the degradation rate of PVC-POM/TiO2 film is 1.5 times higher than that of PVC-TiO2 film under the identical conditions. The enhancement of photocatalytic activity is due to the achievement of a rapid photogenerated charge separation with the assistance of POM which can mediate photogenerated electron transfering from TiO2 conduction band to dioxygen. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 2048-2053, 2011