Abstract: The Polar Earth Orbit（PEO），which crosses the aurora zone，is a peculiar orbit where the low-temperature plasma and energetic auroral electrons coexist.Therefore，dielectric materials on the PEO spacecraft may be negatively charged 100-1000 of volts when the density of thermal ions is reduced or the flux of auroral electrons become large.In this paper an experimental scheme of wake charging of polar spacecraft was introduced，and a similarity spacecraft model was designed.In the experiments the ion saturation currents in the wake area of different scale model were measured under different plasmas，and the charging potentials of the dielectric materials in the wake were also investigated.