Abstract: In the space radiation environment, deep charging and discharging is one of the key factors threatening the safety of spacecraft. In this paper, the ⁹⁰Sr radiation source was used to simulate the electron environment in GEO and several simulated samples of spacecraft floating conductor structure were tested under different degrees of vacuum, electron fluxes and temperatures. It is shown that the deep discharging is closely related to the structure, and some typical floating conductors could discharge under low charging level. Therefore, to protect satellite against deep charging and discharging effects, we should, besides proper selection of dielectrics, avoid the presence of floating conductor structure while considering the influence of vacuum and temperature.