Abstract: Large-scale space simulation of high field intensity electromagnetic environment is difficult to test radiation effects, and there are gaps in the application of existing BCI (bulk current injection) technology to nonlinear system tests. The research on the equivalent alternative radiation test method of the shielded cable coupling channel is carried out. Taking the equal response of the tested equipment as the equivalent basis, an analysis model of the response of the EUT (equipment under test) under the two conditions of radiation method and injection method is established. The equivalent corresponding relationship between the injection excitation source voltage and the radiation field intensity is deduced, and the conditions and test methods for the equivalent replacement of radiation with BCI are proposed and verified by experiments. The research results show that the BCI method can be accurately equivalent to the radiation effect test of the EUT, and the test error does not exceed 2 dB, which can meet the actual needs of the project.