Abstract: This paper prestnts the calculations of the worst-cast high energy electron flux of MEO against the satellite's orbit position and the daily-averaged electron spectra by using the general DICTAT model. For the selected four kinds of typical dielectric materials, we analyzes their charging characteristics in the environment of MEO. The results are compared with those in GEO. It can be concluded that usually, the internal charge risk in MEO is about three times higher than that in GEO, and the charged potential shows obvious fluctuations in the whole orbital period, with 0.3-0.9 h of delay of the high of the charged potential in contrast to the high of the electron flux. The overall profiles are determined by the time constants of the dielectric materials.