Abstract: A series of tests are conducted on the permeability characteristics of sandy gravel with high fines content. It is found that the permeability coefficient of sandy gravel decreases with the increase of the particles less than 5 mm and the relative density. The change of permeability coefficient with the relative density can be described by the semi-logarithmic formula, and the change of permeability coefficient with the content of particles less than 5 mm can be described by the power function. By using the normalization method, the empirical formula is proposed to predict the permeability coefficient of sandy gravel for overburden in Poyang Lake area. The seepage deformation of sandy gravel with high content of particles less than 5 mm is characterized by the soil flow failure or transitional failure. With the increase of the content of particles less than 5 mm and the relative density, the transitional failure turns to the soil flow one.