The variation of surface roughness of the workpieces by Oils-on-Water(OoW)cutting was studied through orthogonal experiment,and the experimental results were compared with dry cutting.Empirical formula of surface roughness applied to austenitic stainless steel was obtained based on the multiple linear regression analysis of surface roughness data.Variance analysis shows that the empirical formula has highly significant linear relationship.The results of test show that a more ideal surface roughness can be obtained for OoW cutting in higher cutting speed,smaller feed rate and greater cut depth compared with dry cutting,and the lower surface roughness of workpieces can be obtained for OoW cutting at the equal cutting efficiency. 