The FFT analytic technique based continuous-wave Doppler radars are extensively used in test range, the true resolution of Doppler shift is dependent on the analyzed signal length by FFT. Concerning the problem that the FFT has limitation of velocity resolution, the CZT calculated on unit circle was proposed, in which the input signal length is unequal with the output signal length, the frequency spectrum can be refined without increasing the radar signal length. Simulation results show that the CZT is superior to the FFT in velocity resolution, the ability to distinguish multiple targets is enhanced by the proposed algorithm.