Abstract: The pattern of plate-plate electrodes with the gap of 2 mm and the discharge current peak of 22 kA is used to compare and research the erosion characteristics of the brass and W-Cu electrodes. The mass loss of the eroded electrode during the pulsed discharge process can be obtained by a high precision balance. Then, the erosion rates of the anode, cathode and total average erosion rates of the electrodes can be calculated, respectively. The micro morphology analysis about the surface of the eroded electrode and the comparison about the content of the metal ions will help to investigate the erosion mechanism of metal electrodes in water. The results show that anti-erosion performance of the W-Cu is obviously better than that of the brass under pulsed discharge in water. For the brass electrodes, large amounts of holes and craters in the central area and the wave structure in the edge area indicate that sputtering of the molten metal is the major erosion form while the unique protuberances and relatively smooth surface of the W-Cu electrode imply the action of the vapor-phase erosion. When regarding Joule heating effect as the powerful catalyst, the electrochemical reaction of the W-Cu behaves more fiercely than that of the brass. Therefore, its unreasonable to neglect the influences of the electrochemical corrosion on the eroded surface when the pulsed discharge occurs in water.