Abstract: The vacuum gap,consisting of sphere (cathode) plane(anode) with specific structure is used to simulate a micro discharging process between electrodes in the special vacuum device. The crystal TiB 2 film of high conjunctive intensity can be deposited on the cathode sphere with the IBAD (ion beam assisted deposition) technology. Experiment result demonstrates that its surface isn’t oxidized by contrast with the stainless steel at 1 000 ℃. Under the single pulse high voltage, the film shows feeblish discharging characteristic after the bombardment of the high energy microparticles at hundreds times. This can increase the voltage holding capability and reduce the dynamic load of pulse power.