The arc erosion behavior of CuCr25 cathode material in oxygen, argon, and carbon dioxide atmospheres under voltage of 9 kV was studied. The arc duration and arc energy are decreased with changing the atmosphere in the order of oxygen, argon, and carbon dioxide, whereas the variation trend of breakdown strength is opposite. The erosion morphologies of molten pools, bulges, holes, splashes, and cracks formed on the CuCr25 material surface under the high temperature and high energy of the arc were analyzed by scanning electron microscope and three-dimensional laser scanning confocal microscope. The results indicate that the most severe erosion occurs in oxygen atmosphere and the slightest erosion occurs in carbon dioxide atmosphere, which can be attributed to the differences in arc energy. According to the results of X-ray photoelectron spectroscopy analysis, the oxidation reactions in oxygen and carbon dioxide atmospheres produce CuO, Cr₂O₃, and CrO₃, while no new compounds are formed in argon atmosphere.