<p>Estimating the mechanical properties of fractured rock masses is a key issue in rock engineering projects. The parameters of strength, deformability, and Poisson’s ratio of intact rock can be measured in the laboratory; however, obtaining these parameters in fractured rock masses is more challenging due to the complexity of fracture networks. So, numerical methods provide a practical approach for determining these properties. In this study, a series of numerical experiments were carried out to examine the influence of model dimensions and fracture density on the deformation modulus, strength, and Poisson’s ratio of fractured rock. These simulations utilized the discrete fracture networks-discrete element method. The results showed that the changes in three parameters depended on the model size. It was observed that with the increase in the model size, the variations in these parameters generally decreased. The increase in fracture density resulted in an increase in the representative elementary volume (REV), and this increase in fracture density led to a decrease in three parameters in the REV. At maximum fracture density, deformation modulus, strength, and Poisson’s ratio decreased by 67%, 89%, and 67% compared to the corresponding values of intact rock, respectively.</p>