The morphology of random screens with different surface roughness is studied with atomic force microscope and it is found that their height distributions have very obvious fractal characteristics in short range regions.For screens with larger and smaller roughness,the fractals exist in the forms of random height fluctuations and small grains without characteristic size respectively.The self-affine fractal surface model is introduced to the quantitative descriptions of randomscreens.The light scattering measurements show that:(1)the scattered intensity in off-axis region descends in negative power functions,and the theoretical analy sis based on self-affine fractal model indicates that it originates from the sho rt-range fractal of the screens;and(2)there is a halo ring in the scattered fiel ds in the paraxial region .This phenomenon cannot yet be explained on the basis of the self-affine fractal model.