Abstract: A general method called time-shifting correcting method of phase difference on discrete spectrum is presented. That is, the second discrete-time sequence lags behind the first one with L points, then performing N -point FFT analysis on both sequences, and finally correcting spectrum by making use of the phase difference of two corresponding peak lines. The method proposed by XIE Ming et al. is just the particular case of this method in the case that L is equal to N. Simulation result shows that this method is easily carried out with high precision, applicable for all kinds of symmetrical window functions and having high ability of anti-noise.