Abstract: In order to verify the feasibility of vacuum butt contact with short gap as protective appliance in aviation variable frequency (360~800Hz) power system, a vacuum chamber with the contact diameter of 20 mm and contact material of Cu-W-WC is selected in this paper to do arc characteristic experiment under the condition of 3 mm gap. Based on the magneto hydro-dynamics theory, the multi-physics simulation model for intermediate frequency vacuum arc is established as well. The results show that the energy of intermediate frequency vacuum arc in butt contact with short gap is low and erosion on the contact surface is light, and no anode spot is formed when the interruption fails. In the high current mode, the symmetrical cylindrical arc can be merged by the magnetic field of the current, and the diffusion vacuum arc is formed at the peak. The current interruption ability of butt contact with short gap decreases slightly with the increase of frequency and is greater than 12.4kA in 360~800Hz, which meets the requirements of aviation variable frequency power system.