In order to establish the qualitative and the quota relations between the technical and tactical parameters of high power microwave weapon(HPMW) and the guidance radar target detection, target parameter measurement and tracking of specific performance indicators and so on. Based on stepped frequency-linear frequency modulated (SF-LFM) radar system, this paper studies the damage of HPM radiation on guidance radar detection unit of this system in signal and information processing performance, by using the Monte Carlo simulation experiment, it obtains the qualitative and quota relations. Between performances like guidance radar range resolution, distance measurement precision, energy accumulation efficiency and so on and intensity and relevance of scope and phase noise under the effect of the high power microwave radiation.