The radiation effect of several typical power electronic components is analyzed, including single total ionizing dose effect, single neutron radiation effect, the sequence radiation effect of neutron-total dose and the synergic radiation effect of neutron-total dose, to get the failure threshold. Experiments show that electronic components irradiated by both neutron and γ-ray have a lower failure threshold than components radiated by single neutron or γ-ray. The mechanism of synergic enhancement damage in bipolar process devices is analyzed. The main reason is that the ionization damage produces positive oxide charge in the oxide layer of the transistor, which increases the surface potential of the base region, increases the number of interface states, reduces the difference of the carrier concentration on the inner sub-surface of the Si body, and intensifies the degradation of current gain and enhances the transistor neutron displacement damage. It is more practical to evaluate the comprehensive radiation resistance of the device according to the synergic radiation test. The research results are of great significance for the evaluation of the radiation resistance of the device.