The objective of this paper is to investigate the influence of spark conditioning on the surface condition of the rod-plane electrodes in vacuum. By comparing the condition of the electrode surface before and after the spark conditioning

the influence of the conditioning process of Cu and SUS304 electrodes on the surface conditions of the electrode is studied respectively. At the same time

A current-limiting resistor is added to the experimental circuit to study the influence law of different breakdown energy on the electrode surface condition. It is revealed by the experimental results that for the vacuum gap of Cu electrode

the surface condition of the electrode after spark conditioning is not related to the electrode initial roughness but to the breakdown energy in the conditioning process. The smaller the breakdown energy is

the smoother the electrode surface is. Thus

the smaller breakdown energy could improve the dielectric strength of the vacuum gap higher

while the difference of dielectric strength of the vacuum gap with different initial roughness after the spark conditioning is nearly the same. For the vacuum gap of SUS304 electrode

the larger the initial roughness of the electrode is

the larger the conditioned area is and the higher the dielectric strength is. At the same time

the larger breakdown energy could enlarge the conditioned area and improve the dielectric strength of the vacuum gap.