An image processing method for conducting anisotropic diffusion filtering on a pixel value I.sub.i,j in a two-dimensional image, comprises: finding conduction coefficients C.sub.n, C.sub.s, C.sub.w, C.sub.e, C.sub.nw, C.sub.sw, C.sub.ne and C.sub.se in eight surrounding directions for each pixel based on a pixel value gradient .gradient.I to produce a two-dimensional distribution image of the conduction coefficients; and finding pixel value first partial differentials .gradient..sub.nI, .gradient..sub.sI, .gradient..sub.wI, .gradient..sub.eI, .gradient..sub.nwI, .gradient..sub.swI, .gradient..sub.neI and .gradient..sub.seI in the eight surrounding directions for each pixel to calculate a pixel value in an output image according to: .times..times..lamda..gradient..times..gradient..times..gradient..times..- gradient..times..times..function..gradient..times..gradient..times..gradie- nt..times..gradient..times. ##EQU00001## (n: the number of times of repetition, .lamda.: a constant).