Abstract: The morphological feathers of rock structural faces with different roughness and undulation are studied quantitatively by theoretical analysis and numerical simulation in this paper. An emphasis is made on the relationship of the morphological parameters of structural faces and the characteristic parameters of principal morphology. Their sampling effects is also studied. A series of results obtained has a great significance to choose rationally the morphological parameters of surface when the interrelation between the morphological parameters of surface and physical quantities is set up, and provides a basis for the choice of rational sampling interval and minimum sampling length.