Comparative study of the catalytic electrooxidative abilities of RuOx-PdO/Ti and RuOx-PdO-TiO2/Ti were conducted using Active Orange 5R solution as simulated wastewater. RuOx-PdO-TiO2/Ti anode possesses higher catalytic oxidation ability, as compared to RuOx-PdO/Ti, in both direct oxidation and indirect oxidation processes. RuOx-PdO-TiO2/Ti could provide a discoloration rate of 98.14% within 30 min, while the COD removal could reach 51.43% in 120 min. It was indicated that higher electrooxidation ability could be achieved at RuOx-PdO-TiO2/Ti anode, which exhibited lower chlorine evolution potential and higher oxygen evolution potential probably resulted from the higher oxidation states of Ru and Pd. (C) 2010 Elsevier B.V. All rights reserved.