Abstract: In this paper, the relation between anisotropic permeability of earth dam core and its stress condition is investigated by means of the stress controlled tests conducted in the triaxial cell. It is shown that the permeability of earth dam core decreases with the increase of effective stress, and the permeability anisotropy of layered soil varies with its stress state. It is therefore suggested that the stress controlled triaxial permeability test may be more useful than ordinary test to determine accurately the permeability coefficient of undisturbed samples taken from a rolled earth dam core.