Abstract: The acoustic features related to western instrument timbre,including the distribution of harmonic energy,cepstrum and Mel-frequency cepstral coefficients(MFCC),and the mechanism sound MFCC(MSMFCC) which is proposed in this paper,are investigated under the multiplication model of musical sound.Features are extracted from pure tone of western orchestral instruments,and their influences on timbre are assessed through analyzing each feature pattern.Results show that:MFCC and MSMFCC emphasizing the nature of excitement perception can reflect timbre difference very well;MSMFCC is more capable for instrument classification;The distribution of harmonic energy,which reflects only the properties of resonator,can differ timbre to some degree;Complex and real cepstra have limited ability to distinguish the different instruments.