This study focuses on the removal of the methyl orange (sodium p-dimethyl amino azo benzene sulfonate) of a representative dye compound in a liquid photo-system using nanometer-sized Zn-incorporated TiO2 Synthesized by a solvothermal method. The Zn-incorporated TiO2 particles exhibited a mixed structure of anatase of TiO2 and ZnTiO3 with a particle size of below 20 nm. The absorbance was shifted to the higher wavelength on 2.0 mol% Zn-incorporated TiO2 Compared to pure TiO2. In the XRD pattern, the structure of ZnTiO3 was seen at 2 theta = 31.75. The XPS result of O 1s confirmed that 2.0 mol% Zn-TiO2 had a higher hydrophilic property (Me-OH/Me-O = 0.46) than pure TiO2 (Me-OH/Me-O = 0.25) did. Based on these results, the photodecomposition for methyl orange in liquid reaction was enhanced over Zn-incorporated TiO2 compared with pure TiO2: methyl orange of 10 ppm was completely decomposed after 120 min over 2.0 mol% Zn-incorporated TiO2. (C) 2008 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.