Abstract: The permeability coefficients of coarse-grained soil are closely related to soil types， material composition， grain composition， particle shapes and density. Based on laboratory tests， the effects of particle shapes， grain composition and density on the permeability coefficients of the coarse-grained soil have been studied. In order to analize these influencing factors， nine groups of constant head experiments are designed by use of orthogonal test approaches. The influences of three factors on the permeability coefficients of the coarse-grained soil are determined by range analysis and variance analysis. Research results show that the permeability coefficients are increased with increasing of grain composition characteristic value d20 and increasing of curvature coefficient Cc, and decreased with increasing of dry density and increasing of sphericity.