With the expansion of frequency bands and power enhancement of various military and civilian radiation sources, the interference suffered by linear frequency modulated continuous wave (LFMCW) detectors has become more seriously. However, the current researches on the anti-jamming technology for the LFMCW system mainly focus on countering active jamming, and there are few studies on interference from strong radiation sources. To solve the above problems, against the background of the interference of high-power radar radiation sources, two typical radar signals including conventional pulses and chirp pulses are modeled, and the interference mechanism for LFMCW detectors is analyzed. According to the difference between target echo signal and jamming in timefrequency domain, an interference suppression algorithm combining time-frequency transform and edge detection is proposed in this article. In the proposed algorithm, the short-time Fourier transform ( STFT) is firstly used to obtain the time-frequency image of the received signal. Exploiting the periodic truncation characteristics of the pulse interference across the time axis, the interference is coarsely filtered in the time-frequency domain. Then, combined with the edge detection technology, the algorithm adopts the Sobel operator to perform convolution along the frequency axis to further filter out the residual interference, reconstruct the filtered spectrum, and extract the target information. Simulation and experimental results show that the proposed algorithm can effectively suppress the signal interference of two typical pulsed radar emitters, and the accuracy of obtained target difference frequency from the interference background is within 3% .