Abstract: Based on the cyclic triaxial tests of saturated sand in drained and undrained conditions the physical states change including the preliminary negative dilatancy,positive dilatancy, secondary and reversal negative dilatancy and so on were explored completely by the response of pore water pressure under undrained cyclic loading and the volumetrical strain induced by shear under drained cyclic loading . It has been verified that the physical states exist factually so as to provide the basis for studying the deformation properties in complicated stress conditions.