Rock and soil aggregate (RSA) is a special geo-material and composed of hard matrix like gravel, cobble, pebble and soft matrix of soil. Discontinuity and heterogeneity are the main characteristics of RSA and its mechanical response is mainly controlled by its complex internal structure. The rock fragments play very important role in the mechanical performances under the condition of uniaxial compression and the rock content (the volume percent of rock fragments in RSA) of RSA is the focus of this study. RSA models with different rock content based on the structural characteristics were built for the numerical uniaxial test. The strength of RSA decreases instead with the increment of rock contents, stress-strain curves attained in the test reflect five different phases according to the deformation and failure process of samples.