Aiming at the restriction of detecting the acclerating target using traditional DFT method,this paper is based on the discrete Chirp-Fourier transform and the real background in signal detection using missile-borne high-PRF pulsed Doppler radar.A transform naming changing scale discrete Chirp-Fourier transform is presented,and then the performance of the transform is analyzed.Finally,a new cascaded detection method is put forward for detecting the chirp signal using radar.The theoretics and the experiments demonstrates its effectiveness in performance.