The wastewater from textile industries containing non-biodegradable and toxic dye compounds is one important sources of environmental contamination. This study aims at investigating the decomposition of azo dye by UV/H2O2 process with varying H2O2 concentrations, dye concentrations, initial pHs. and UV irradiation powers. The results show that the initial rate increases with increase in initial H2O2 concentration, initial dye concentration to a certain point and then decreases with further increase in the above factors; the initial rate remains almost constant at lower pH and then decreases with increase in pH; the initial rate linearly increases with increase in UV irradiation power. A comprehensive kinetic model. based on reaction network analysis, was developed to predict the effects of H2O2 concentration, dye concentration, solution pH, and UV irradiation power on the initial dye reaction rate. The experimental data and the predicted results are in good agreement. (C) 2009 Elsevier Ltd. All rights reserved.