The invention discloses a radar anti-interference system. The radar anti-interference system comprises a radar receiver, a frequency mixer, an intermediate frequency amplifier, a radar transmitter, an interference investigation processing unit, a main control chip, a distance tracking unit and a modulator. The interference investigation processing unit comprises an interference investigation module and an interference processing unit. The interference investigation module comprises a CFAR detector and an orthogonal two-channel coherent detector. The interference processing unit comprises a canceller, a Doppler filter and a constant false-alarm rate processor. The output end of the radar receiver is connected with the input end of the interference investigation processing unit and the input end of the distance tracking unit through the frequency mixer and the intermediate frequency amplifier in sequence. The radar anti-interference system is easy to operate and high in reliability, distance signals of sum beams are modified through the distance tracking unit, the interference investigation processing unit is used for investigating and processing interference signals, the target detection distance is prolonged, the anti-interference capacity of radar is enhanced, and the practical application prospect is wide.