Abstract: High-altitude electromagnetic pulse (HEMP) can couple into electronic equipment through channels, such as cables and apertures, causing temporary or permanent damage to various electronic systems. Considering the extremely high level of safety protection of nuclear power plants, it is necessary to study the sensibility, vulnerability and protective measures of the electronic systems in nuclear power plants under the radiation of electromagnetic pulses. In this paper, firstly, a minimum safety system of nuclear power plant was determined and built, including electrical, instrumentation, and clock synchronization systems. Then the radiation experimental platform of HEMP was built, and the electrical field waveform of HEMP simulator meets the requirements of GJB 8848-2016 standard. Finally, the electromagnetic pulse radiation experiment was performed on the minimum safety system. Based on the experimental data and effects, a preliminary analysis was performed for the electromagnetic pulse coupling to the minimum safety system of the nuclear power plant, and it is found that HEMP has a certain degree of threat to the minimum safety system of the nuclear power plant, but doesn't affect its core functions. By summarizing the effect phenomena, analyzing sensitive parts and thresholds, this study provides a basis for the following vulnerability assessment and protection strategy formulation.