Synthetic aperture radar(SAR) image after speckle suppression,the edge of the target image will appear fuzzy.In this paper,an improved enhancement approach based on anisotropy differential used for SAR image is proposed,two distribution functions are structured with gradient diffusion coefficient in gradient direction and vertical one in this paper.In non-target region,the extent of the spread is equal to all directions,and the speckle noise has a better inhibitory effect;in the target region,in order to pr...