With the purpose of developing the high efficient electrolytic dressing method for bronze bond diamond wheel of a coarse grain, twin electrode electrolytic dressing method using DC power source is devised and the validity of its method is examined by the experiments. In the larger initial electrolytic current value than the critical value, the electrolytic current value decreases with dressing time until a constant corresponding with dressing conditions because the oxide layer generated by the electrolytic reaction increases with dressing time. In the suitable initial electrolytic current value below the critical value, on the other hand, the electrolytic current value is independent on dressing time because the oxide layer does not increase with dressing time. In the suitable dressing conditions, the grain extrusion height from the bond surface increases efficiently in approximately proportion to dressing time beyond the height of 35μm which is about one-third of abrasive grain diameter of #140 wheel. The grinding performance of wheel dressed suitably by twin electrode method has longer dressing life interval, smaller variation of surface roughness in grinding process and larger grinding ratio than single electrode method. From the results, it is referred that the method is useful for dressing of coarse grain wheel of #140.