Abstract: Whether the time scale t_p/t_m=n² for consolidation and pore water pressure diffusion in centrifugal model tests is correct or not is infact. How the permeability coefficient of soils changes with the centrifugal acceleration. The permeability similarity theory of centrifuge model is derived. The permeability tests of centrifuge model are carried out to study the variation laws of permeability coefficient of soils with the acceleration. The test results show that the permeability coefficient linearly increases with the increase of the acceleration. The permeability in the centrifugal model tests conforms to the Darcy's law. The ratio of the model permeability coefficient to the prototype one k_m/k_p linearly increases in proportion to the acceleration, and the scale factor ≅ 1. It is verified that the permeability coefficient scale in the centrifugal model tests is η_k=1/n. The research results are of great theoretical and application values for the centrifugal model tests.