Abstract: In the application, fast Fourier transform (FFT) algorithm's speed is fast but its precision is worse whereas MUSIC algorithm has a higher precision but its real time aspect is worse. This paper analyses the characteristics of FFT algorithm and MUSIC algorithm. Using FFT algorithm to pre-estimate a signal harmonic frequency and select some effective frequecy range before using MUSIC algorithm to complete frequency search we can reduce the search area and the processing time of MUSIC algorithm greatly.