Abstract: Wavelet analysis method was used to carry out computed analysis of wear particle image and the grain parameter for wear particle image based on statistical feature parameters was suggested as a characterizing parameter for the identification and analysis of the wear particle image. Thus the feature of the wear particles image can be obtained by means of wavelet decomposition and statistics analysis. Test results show that grain parameter can be used as a comprehensive feature parameter for wear particle image analysis, and the results based on the computed analysis agree well with the testing ones.