Abstract: This project is to quantify the 3D surface characteristics of wear particles using 3D surface roughness parameters and 3D surface texture index. Roughness average, root mean square, surface skewness, surface kurtosis and surface texture direction index are employed. Application examples on wear particles are presented in the paper to demonstrate that 3D surface roughness and texture parameters can describe surface characteristics of wear particles reliably and distinguish different types of wear particles significantly.