Abstract: To solve the problem that high power signal may be tracked by anti-radiation missile in coherent interference, a novel cancellation interference method based on phase modulation is proposed. The kernel thought is to produce cancellation signal according to radar signal and its phase modulation information so as to protect target through the cancellation between radar signal and interference signal. Characteristics of several typical pulse compressed signals are analyzed. Mechanism of signal cancellation's influence on filtering output was explained through the group delay function. Then connection between cancellation error and cancellation effect is explained. The implementation method of cancellation signal and the effect evaluating indicator are provided. Simulation results show that the proposed method could reduce effectively the detecting probability of radar to that below 50% through canceling interference, which can provide reference for targets' active stealth.