Cds/TiO2/polymer nanocomposite thin films (CdS/TiO2/polymer NTFs) as photocatalyst were prepared and characterized by wide angle X-ray diffraction (WXRD). The effect of key operational factors, i.e. catalyst amount, H2O2 dosage, solution pH, initial dye concentration, coexisting anions and reuse of catalyst on decolorization of methyl orange (MO) was investigated systematically. WXRD results indicated that CdS/TiO2/polymer NTFs presented a mixture of anataseTiO(2) and hexagonal CdS nanocrystals. 99.5% of MO was successfully decolorized after 130 min simulated solar light irradiation at 3.9 mmol L-1 H2O2, 1.0 g L-1 CdS/TiO2/polymer NTFs and pH 6.0 for 15 mg L-1 MO aqueous solution. All examined anions (Cl-, NO3-, SO42-, CO32- and PO43-) had an inhibitory effect on the decolorization of MO. When the photocatalyst was used for the fifth time, decolorization efficiency was still about 99% after 130 min irradiation. These results demonstrated that H2O2 assisted CdS/TiO2/polymer NTFs under simulated solar light irradiation was an effective and promising process for decolorization of dye-containing wastewater. (C) 2010 Elsevier B.V. All rights reserved.