By the uniaxial compressive strength test in laboratory, the mechanical properties of the cemented sand and gravel(CSG)material were investigated under the conditions that cement contents were 40 kg/m³, 60 kg/m³, 80 kg/m³, and 100 kg/m³, respectively. Experimental results show that as the increase of cement content, the elastic modulus and compressive strength gradually increase, and their mechanical properties gradually evolve from those similar to rockfill materials to those similar to RCC. In order to study the failure mechanism of material, the lattice discrete particle method(LDPM)was used to establish a meso-scale model, and the crack propagation behavior under the uniaxial compression was simulated. The curves fit well with the experimental data. In addition, from the cloud diagram of crack opening, there are almost no cracks in the elastic stage. After the axial stress reaches the compressive strength value, the crack gradually initiates and expands, finally forms multiple fractures parallel to the pressure direction, and causes damage to the specimen. The cracks mainly extend along the interfacial layer between mortar and aggregate, while the aggregate is not broken at all. The results show that the formation and developing mechanism of meso-crack of CSG material can be effectively simulated by the LDPM.