Abstract: The three-dimensional deformable discrete element method is employed to study the rockfill at mesomechanical level . The aim of this study is to explore the relationship among the particle shape, mesoscopic mechanical parameter and macroscopic response of rockfill. The simulated results show that the particle shape has a significant impact on the macroscopic response, that is, the larger the aspect ratio of the particle, the larger the the peak and residual strengths of the numerical samples, whereas the smaller the value of the initial modulus of the samples, because components of the internal friction angle produced by the rearranged particles will become larger if the aspect ratio of the particle becomes larger. The inter-particle friction angle also has a great impact on the macroscopic response of rock fill, namely, with the increase of the inter-particle friction angle, the peak strength and initial modulus both increase significantly, what is more, the volume shrinkage mass of the numerical samples also has a markable increase during the shearing process, which reflects the interaction between rockfill particles and the macro-mechanical behaviors of the particle skeleton.