Abstract: The main component of the vacuum switch arc is the metal vapor generated between the electrodes during the fault current breaking process, and the micro dynamic behavior of the vacuum arc directly affects the breaking ability of the switch. In this paper, the two-temperature magneto hydro dynamic(MHD) model of vacuum arc is established to study the anode thermal process of vacuum switch equipped with CuCr alloy contact electrode of different proportions under fault current interruption, and the distribution of anode surface temperature and melting pool range along the radial and axial direction is obtained. The simulation results indicate that the increase in the breaking fault current and Cu content in the electrode alloy will lead to the increase of energy flow density for the input anode. Under 200 A arc current, the surface temperature of the anode did not reach the melting point of CuCr alloy and did not melt; Under 6 kA arc current, the anode temperature reached the melting points of Cu and Cr successively, and the melting degree of the electrode weakened with the increase of Cr content in the alloy.