Abstract: To research the deformation and failure of coal-rock combined body, based on the engineering and geological model, the mechanical properties of contact surface of coal-rock combined body were analyzed and summarized in this paper. Parallel bond numerical model of coal-rock combined body was established based on particle discrete element program, and generation and propagation process of mesoscopic cracks are analyzed under the uniaxial compression. Results showed that the deformation and failure process of coal and rock mass is the progressive failure process of coal body damage first, rock body damage and fracture until the overall instability due to the restraining effect of coal-rock interface on the deformation and failure of coal body.