The primary objective of this study is to investigate an anisotropic permeability through a single rough rock joint and its characteristic change due to shear displacement. Permeability approximation, which is represented by statistical first and second moments of aperture distribution, was used for this purpose. The shear-induced remarkable increment and anisotropy in the joint permeabilty were simulated, and their characteristics by a different spatial correlation function (; Gaussian and Exponential) of surface roughness were demonstrated. Obtained results were compared with those of Monte Carlo Simulation so as to present the validity of the current approach.