Abstract: Based on the research and analysis of the β radiation distribution characteristics in the nuclear power plant within a severe accident, the radiation distribution is calculated when β radiation works on the typical instruments and when.  γ radiation works on the same typical instruments. The β radiation harm influence is converted into a certain percentage of γ radiation through the way of energy equivalence, to obtain the β radiation damage quantitative data and the β radiation shielding performance data of different materials. At the same time, it provided the quantitative test radiation value in severe accident qualification. The research result can be used in engineering practice directly for conducting the instrumentation survivability analysis, equipment qualification and equipment design.