IrO₂-Ta₂O₅-MnO_x electrodes with different Mn contents were prepared. The effect of Mn content on the physical and electrochemical characteristics of these electrodes was revealed. The results show that the coated IrO₂-Ta₂O₅-MnO_x layer has a larger specific surface area due to its bumpy and porous structure. The doping of a small amount of Mn inhibits the crystallization of the active ingredient IrO₂ and turns it into Ir³⁺. With properly replacing Ir with Mn, the electrocatalytic performance of the IrO₂-Ta₂O₅-MnO_x electrodes can be enhanced dramatically. The increased electrocatalytic activity, longer lifetime and lower cost benefit from the larger active surface area of the Mn-doped electrode, thus promoting the release of oxygen in the sulfuric acid solution.