In order to design Ru-based oxide-coated catalyst electrodes with a large surface area, the following five methods were evaluated and the electrochemically active surface area of the electrodes were compared. (1) The addition of sodium carbonate to an alcoholic dipping solution for a drip-coated RuO2/Ti electrode; (2) the preparation of RuO2-MOx (M, dopant metal)/Ti electrodes by dig-coating method; (3) the preparation of RuO2-ROx (R, rare earth element)/Ti electrodes by dip-coating method followed by dissolution of RO, by acid to form meso-pores; (4) the addition of ammonium hydrogen carbonate salt as a catalyst in a sol-gel process for the preparation of ultrafine RuO2 particles; and (5) the transformation of RuO2 into a layer structure; HxRuOy. All these preparation methods developed by these authors, although method 2 is a conventional one, were shown to be very effective for increasing the electrochemically active surface area of the Ru-based oxide electrodes. Each of these methods has a potential to design the active oxide electrocatalysts.