Abstract: Internal charge is an important space environmental effect affecting the safety and normal operation of spacecraft in orbit. The deposited charge distributions in dielectric materials under high-energy electron irradiation is an important factor of internal charge effect. In this paper, the deposited charge distributions in polyimide (PI) materials irradiated by 0.3 MeV to 1.0 MeV electrons was tested by pulsed electro-acoustic (PEA) method. The effects of electron energy and number of incident electrons on the internal deposited charge distributions were studied. The results show that high-energy electrons are mainly deposited at the back end of the irradiation region. With the increase of the number of incident electrons, the amount of charge deposited inside the materials would continue to increase and eventually reach a stable state. The electrons with higher energy have greater penetration ability, resulting in charge deposition peaks with a wider range inside the materials.