Abstract: Traditional stress dilatancy theory had been extensively used in constitutive modeling,and its application to clay was very successful.However it was found that this theory was not suitable for sand modeling due to the ignorance of internal state variable of materials in the definition of dilatancy equation.This problem had been recognized by some researchers in recent years,and some variables related to material state were combined into the dilatancy equation.The so called state-dependent dilatancy theory was suggested and applied in sand modeling.In this paper,the description of sand state,the development of dilatancy theory and constitutive modeling of sand behavior were introduced.