Abstract: A method based on multiple signal classification(MUSIC)algorithm is proposed to process the helicopter radiated acoustic signal with random noise under the condition of the assumption that is the signal and noise are mutually uncorrelated. This paper introduces the MUSIC spectrum estimation method, and then uses the traditional method and MUSIC algorithm to process the signals radiated by different types of helicopters. The results show that MUSIC spectrum estimation can suppress the noise, extrude the peak of spectrum to improve signal to noise ratio obviously and reflect the harmonic characteristics of helicopter acoustic signal accurately.