Abstract: This paper studies the principle of radio frequency limiting of PIN, and analyzes how the spike leakage occurs in EMP protection and how to restrain it. On this basis, the structure of passive multi-stage PIN diode is adopted. Through the establishment of its field simulation model, the corresponding S parameters are extracted, and the optimal matching network is optimized. The electromagnetic pulse protection module which works at 1-200 MHz with insertion loss of less than 0.15 dB, VSWR of less than 1.4 dB, response time of less than 1ns is designed. Combined with PIN diode model, ADS simulation software is used to simulate the limiting performance of electromagnetic pulse protection module. The result shows that all the indexes meet the requirements.