For a long time sequence radar signal, fast Fourier transform (FFT) needs large computation, In order to solve this problem，the paper proposes to use sparse Fourier transform (SFT) for radar signal processing, due to the actual radar target Doppler frequency numbers is limited , to meet the SFT method using conditions. In the paper, the SFT filter parameters and segment length selection are analyzed and discussed, and gives the SFT mathematical expression of the radar signal processing; Finally, the performance of the proposed method is validated with simulation data, the results show that the SFT is superior to the traditional methods in computational speed, and the estimated speed of the target signal parameters can be improved.