Abstract: The material properties of CuW alloy, used as electrode material in large current vacuum contactors, influence the operational performance and service life of the vacuum switches. Due to the differences in the physical properties and crystal structures between the Cu phase and W phase, the microscopic damage behavior of CuW electrodes under the influence of arcs exhibits distinct characteristics. In this paper, a dual-temperature particle model of CuW80 alloy electrodes is proposed, and the ablation process is simulated under different power densities. Simulation results show that the increase in power density exacerbates the surface temperature of the electrodes rise, thermal diffusion, and local thermal stress during the arcing process, resulting in an increase in electrode mass loss and ablation depth, and a persistent evaporation phenomenon, exhibiting non-equilibrium evolution characteristics. At low power density conditions, the temperature rise shows a relatively mild variation, the electrode surface erosion is light, and the thermal stress is concentrated in a local area; at high power density, the surface rapidly melts and undergoes violent evaporation, leading to intensified interface thermal damage and more severe electrode damage. Non-uniform heat transfer in the CuW two-phase structure causes interface damage.