Dense sand normally exhibits shear dilatancy softening under normal pressure and shear shrinkage hardening under high pressure. Therefore

unified model of sand and its numerical implementation is an important scientific problem for describing the loading response of dilatancy softening material

and it will also promote the progressive failure theory. In this study

the unified model of sand which reflects the mechanical properties of dense sand under normal and high pressure is firstly described

and then the key problem of numerical calculation for the model is analyzed. By using the explicit method

the secondary development of stress integration program is carried out. In the process of stress integration

loading-unloading criterion within strain space and smoothed failure surface are used for satisfying the judgment of loading condition and determination of plastic strain direction. An example is given to prove that the explicit method can overcome the difficulties in calculation for dilatancy and softening. This method shows a good way to analyze the mechanical behavior for materials with dilatancy softening and shrinkage hardening characteristics.