Abstract This paper discusses a statistical approach for determining the roughness of a ground surface by considering the dressing characteristics of the grinding wheel. The statistical analyses are derived for the distribution curve of the cutting edges and the probability density function for the occurrence of “peaks” throughout the surface profile of the grinding wheel after dressing treatment and the root mean square roughness of the workpiece surface ground by the wheel. The theory shows that when the grinding wheel is repeatedly dressed by a sharp-pointed dresser, the distribution curve of cutting edges is parabolic. The root mean square of the surface ground by the cutting edges may be calculated from wheel speed, wheel diameter, workpiece speed, the apical angle of the dresser, size sample and the distribution of cutting edges on the circumferential direction of wheel. Good agreement was found between theoretically calculated and experimental results.