The high power microwave (HPM) can entered into the equipment by the antennas of radar and electronic warfare equipment . A good coupling ability and large peak amplitude of this coupling method lead to a greater probability to cause electromagnetic interference or damage to the equipment. As a result, it is necessary to investigate the HPM damage effects to electronic devices as well as the protective measures. In this paper, as there are few researches on high-power microwave effects at the equipment level, an X-band microwave receiver front-end is taken as an equipment under test (EUT), and the injection experiment is carried out to study the high power microwave damage effects. The effect phenomena and data are obtained. The results show that when the limiter is protected, a single HPM pulse with an amplitude of 48.8 dBm can cause damage to the low-noise amplifier of the microwave receiver front-end. If an amplitude limiter is employed in the receiving circuit, the threshold of damage HPM power needs to be increased to 60.7 dBm and the number of pulses can be increased to 100. It also reveals that energy deposition is the necessary condition for performing damage. Both a narrow microwave pulse with relatively high peak power and a series of wide pulses with relatively low high peak power can cause fatal damage to the sensitive devices. The damage effect can be enhanced if the key parameters of the HPM weapon are optimized, i.e., the peak power, the pulse width and the number of pulses. Furthermore, the attacking distance and mechanism of the typical HPM power weapons are also discussed, which is helpful for effect evaluation as well as protection design for radar and electronic warfare equipment.