Indirect anodic oxidation of anthracene achieved by using both chloride anion and ruthenium cation redox double mediator in a multiphase system was studied. Factors affecting the current efficiency of anthraquinone were explored. The results revealed that the highest current efficiency of anthraquinone reached 78%. The current efficiency was mainly affected by the amount of electricity passed, the RuO2 and KCl double redox mediator, the kind of electrolyte used, the concentration of anthracene, the agitation rate, the concentration of KCl and the pH value. Further, the current efficiency was slightly affected by the anode current density and the concentration of RuO2.