The purpose of this study is to obtain the estimation of the electromagnetic interference caused by the antenna feed system to the given equipment nearby, so as to optimize the design parameters of the antenna feed system. In this study, the magnetic field module in COMSOL is utilized to simulate the electric field intensity and current density excited by the whole antenna feed system under the external electromagnetic field. The model space is truncated by infinite element domain. The induced current is mainly distributed on the inner and outer surface of the solid of the antenna feed subsystem, and its value is generally about 650 A/mm2, while the induced current in the solid of the antenna feed subsystem is less than 6 A/mm2. For the region with thin wall, the induced current in the solid is also large. For a given excitation, the wave reaches two line probes at the same time and produces induction current. The simulation results show that the coupling electromagnetic effect of the antenna feed subsystem on the external radiation electromagnetic source is mainly concentrated on the surface of the solid part, which causes the signal to change and has a great effect on the bit error rate.