Abstract: In order to extend terrain classification methods and improve accuracy,a terrain classification method based on acoustic signal was proposed.An acoustic pressure sensor was installed to acquire acoustic signal resulted from tracked robot-terrain interaction.The modified MFCC+△MFCC feature vector was extracted.Finally,a tuned support vector machine(SVM)was adopted to perform classification.The results indicate that the information carried by the acoustic signal is able to characterize terrain type.The modified MFCC+△MFCC feature vector is obviously superior to features extracted from amplitude domain,frequency domain and time-frequency domain.The highest accuracy of 89.5% is achieved in campus environment.When the SNR is higher than 20 dB,accuracies around 80% can be achieved in various background environments.Acoustic-based method is proved to be effective in terrain classification application.