Abstract: The rockfill material is one kind of granular materials graded by angular particles obtained by blasting parent rock or gritting materials collected from river beds. Rockfill materials are used for constructing high concrete face rockfilled dams(CFRD) and clay core rockfilled dams in hydropower engineering, which is the main part for supporting the water pressure in the structure of dams. Based on the disturbed state concept (DSC) suggested by Desai C S for sand clay, an elasto-plastic constitutive model is developed in order to precisely reflect the complicated mechanical behavior of rockfill materials in this paper. The major works are as follows: 1) the full adjusted state of rockfill materials is appropriately characterized as a critical state, according to the evolution character of internal microstructures of rockfill materials, considered the effect of the plastic volumetric strain in disturbance function to reflect barotropy properties of rockfill materials. 2) According to large-scale triaxial test data, suggested the parameter determination methods of the constitutive model. 3) numerical calculation were verified and compared with the data from triaxial compression tests of rockfill materials for one national projects, the results show that the DSC model can simulate some main mechanical properties of rockfill materials, such as the nonlinearity, barotropy, dilatancy and grain fracture, and can characterize the effect and evolution process for the stress and deformation of granular materials in complex stress path.