To analyze the influence of microscopic parameters on deformation properties of rockfill materials in triaxial test simulation with discrete element method (DEM), a control variable method was adopted to determine the influence on stress-strain and volumetric strain curves. In addition, the influence mechanism was explained. Firstly, the characteristics and development trend of triaxial test simulations of rockfill materials were summarized in detail, and it is determined that the contact bond model is the best choice for simulating triaxial tests of rockfill materials. Subsequently, a detailed DEM model of the triaxial test of rockfill materials was established to study the influences and mechanism of friction coefficient, normal and shear stiffness, normal and shear bond strength. Finally, the relationship between deformation properties and broken bond of rockfill materials was investigated. It is considered that the broken bonds of rockfill materials were obviously influenced by microscopic parameters, and the deformation properties were significantly affected by broken bonds. Therefore, in this paper, the influence of microscopic parameters on the deformation properties of rockfill materials was explored, providing a reference for the calibration of microscopic parameters and laying a foundation for the characteristics research of rockfill materials.