Abstract: Space ion electric propulsion has been widely used in the north–south position maintenance and orbit transfer missions for high-orbit satellites. However, unexpected electric breakdown by ion electric propulsion systems is still a challenging problem that needs to be solved, as it affects reliability. Based on the analysis of in-orbit and ground test data of ion thrusters from simulation and experimental results, the main influencing factors of induced electric breakdown are clarified and the mechanisms of induced electric breakdown are analyzed. It is found that the main factors inducing breakdown are the voltage and electric field strength between the grids. In addition, by monitoring the waveform of plasma discharge, the temporal characteristics of breakdown can be defined as three stages of “breakdown–spark–loop response”. Thus, three kinds of engineering suppression methods for breakdown of static vacuum with periodic short-term heating, electrode surface polishing and sealing insulation with plasma, add energy suppression circuit are carried out, and the experimental results show that the electric breakdown frequency can be reduced by about 30%.