Abstract: This note gives a concise discussion on the relation between the center line average Ra and the root mean square Hck of surface roughness on different conditions in grinding. It points out some mistakes in the theoretical analysis involved in the reference [1]. According to the theoretical formulae of Ra and Hck involved in the author's paper [5], the following conclusion has been drawn, The value of λdepending on different grinding conditions varies within the limits of 0.222 to 0.532. Experimental data are given herewith.