Abstract: Wear of materials extremedependson contour shapes of graih,Baseed on Fourierseries analysis in frequency domain,the numerical calculation of grain contour shapes is completed in personal computer.Grain sharpness,roughness and other contour parameters areeasily obtained from the numerical calculation. This provides an effective method for determingand comparing the contour shapes of different batches of grains. By using three-body abrasiontests ,the sensibility of different shape parameters to change of grain batches is evaluated.It isshown that the parameter Va,the sharpness of grain,is much more sensitive to change ofgrain batches than other kinds of parameters. Thus,the parameter Va should be firstly chosento evaluate the contour shapes of grain in abrasion,