The mechanical behaviors of rock masses are significantly affected by the distribution and shape of the holes in it. In this research, the fracture mechanism and the shear properties of rock masses containing holes were investigated by the cohesive zone model (CZM) method. At first, a uniaxial compression laboratory test was carried out, and some mechanical parameters were obtained, and then the obtained mechanical parameters were used to build a mathematical model with zero-thickness elements. Subsequently, the numerical shear test was performed under a mixed-mode test, using the obtained mechanical parameters. Finally, the mechanical characteristics and crack behaviors were discussed separately. The results exhibit that the shear process in this research could be determined and identified as the elastic, strengthening, plastic, and residual stress stages, respectively. Note that the shear rate and normal stress of rock masses containing holes are significantly and positively correlated with their shear strength and dilatancy. In addition, the cracking behavior and mechanical properties of the specimens are closely related to the shear rate and normal stress. Overall, the results of this study have great significance in guiding future, in-depth research of rock masses containing holes in rock slopes.