Abstract: The main features of future constitutive models for granular materials in penetration analysis were discussed.A two-dimensional discrete element method(DEM) was used to numerically simulate penetration tests on a granular ground.The stress paths and stress fields in the ground were studied and then compared with the advanced knowledge in soil mechanics in order to highlight the main features of granular materials for the penetration analysis.It was shown that the shear dilatancy,rate-dependency,particle crushing and non-coaxiality were the four main features that should be captured in future constitutive models for granular materials in the penetration analysis.