The invention discloses a method for monitoring inner electrified electric potentials of a spacecraft and belongs to the technical field of anti-radiation reinforcement. The method includes manufacturing an inner electrified probe: the electrified probe utilizes a multi-layer circuit board structure, the inner electrified probe comprises a shielding housing, a multi-layer circuit board, a resistor and an electrometer; and the multi-layer circuit board comprises a substrate, dielectric layers and copper film layers, the substrate is arranged on the base layer, the dielectric layers are arranged on the substrate, and the numbers of the dielectric layers and the copper film layers are ten respectively and the dielectric layers and the copper film layers are crossed and stacked; and performing a electron beam irradiation test and measuring electric potentials at different depths inside dielectrics of the multi-layer circuit board by measuring electric potentials on led wires on the copper film layers. According to the method, electric potentials at points inside the dielectric layers can be monitored in real time, electrons with energy lower than 200keV can be prevented, and accordingly, inner electrification can be only monitored and effects of surface charging are eliminated.