Periodic current oscillation on the anode is reported for the first time in the electro-oxidation of aqueous Mn2+ solution. It originates from the Mn-oxide-catalyzed electro-oxidation of H2O, and shows significant dependence on both the anode potential and the micro-structure of Mn oxides. The oscillation accounts for extra power consumption (>14%). The experimental current time curve well agrees with the preliminary theoretical calculation results, which lead to a hypothetical dynamic mechanism for the oscillation. This work provides insight into the microscopic electrochemical mechanism underlying the macroscopic non-equilibrium phenomenon, and new evidences for the mechanism of Mn-oxide catalyst. (C) 2013 Elsevier Ltd. All rights reserved.