Abstract: To enhance the anti-jamming capability of linear frequency modulation (LFM) pulse compression radar in the complex electromagnetic environment, a method based on time-frequency analysis is proposed to discriminate and suppress interrupted sampling repeater jamming (ISRJ). Aiming at the discontinuities of ISRJ in time domain, the time-frequency distribution of received radar signal is obtained after mixing with reference signal. Then a characteristic parameter is extracted from the time-frequency distribution, which can be applied to discriminate jamming and radar target. By combining stretch processing with time-frequency analysis, a band-pass filtering function is generated first based on the calculated STFT result, which can be used to remove the ISRJ from the stretch processing results of radar received signal. Theoretical derivation and computer simulation analysis shows that this algorithm can discriminate the existence of ISRJ in reasonable signal noise ratio (SNR), and suppress this jamming effectively.