In order to study the influence of gravel size and strength characteristics on the propagation mode and mechanical parameters of glutenite, a heterogeneous core model of glutenite was established by using the rock fracture process simulation system RFPA. The failure process and fracture propagation law of sandy conglomerate core and the variation of elastic mechanical parameters such as compressive strength, Young's modulus and Poisson's ratio with the change of gravel size and mechanical properties were studied. The results showed that with the increase of gravel size, core model of Poisson and Young's modulus increase gradually, intensity, and increase with the decrease of the first and core crack morphology of different gravel size is almost the same; With the increase of gravel strength, the compressive strength of rock uniaxial compressive strength gradually increased, and then remained basically unchanged, mainly determined by matrix strength. The results reproduce the process of crack initiation and propagation of gravel, and the influence law of gravel size and strength on core fracture is obtained.