Abstract: In the high-voltage vacuum interrupter, the effective control of vacuum arc with large gap distance is the key to improvement in the performance of vacuum switch. Therefore, it is necessary to study the microphysical process between the characteristics of high-current vacuum arc plasma and spatial magnetic field under the condition of varying the gap distance. Based on 3-D steady-state model of high-current vacuum arcs, the spatial magnetic field distribution and three-dimensional characteristics of vacuum arc of four-slots-cup-shaped axial magnetic contact and six-slots-cup-shaped axial magnetic contact under different gap distance are simulated and compared in this paper. The simulation results show that the axial magnetic field decreases and the radial magnetic field increases with the increase of gap distance. When the gap distance increases, the axial current density contracts at the anode side, thus the electron temperature near the anode side and the injected anode heat flux density will correspondingly increase. This will cause local overheat in the center of the anode and adversely affect the effective break of the vacuum arc. In addition, the comparison and analysis of simulation results can provide some reference for the optimal design of contacts in high-voltage vacuum interrupter. The ion number density distribution in the simulation results is in good agreement with the arc column shape in the experimental arc photos.