Abstract: During the construction of rockfill dams in seasonal frozen soil or permafrost regions, the permeability of rockfill materials will change due to the effects of freeze-thaw cycles and overburden pressure, which may be closely related to the number of freeze-thaw cycles and the magnitude of overburden load.A large-scale permeability test was carried out under the action of overburden load and the freeze-thaw cycle for the rockfill material of a core rockfill dam in Tibet.The results show that under the same overburden load, the permeability coefficient gradually increases with the increase of freeze-thaw times, and the change is more obvious after three freeze-thaw cycles.When the freeze-thaw cycles are the same, with the increase of overburden load, the permeability coefficient decreases gradually, and the change of permeability coefficient gradually slows down when the overburden load exceeds 200 kPa.The relationship between permeability coefficient and overburden load is power function.