Abstract: Firstly, according to the dynamic deformation characteristics of rock and based on the Kelvin model, a mechanical model to simulate dynamic behavior of rock is established by treating dynamic stress of rock in the deformation process as the summation of two components, which are the static stress and the dynamic stress component. The viscous and the nonlinear elements in the model are used to simulate the above two components, respectively. Secondly, dynamic simulation methods of the deformation process of the viscous and the nonlinear elements are obtained according to the mechanical characteristics of the viscous element and the statistical damage theory, consequently, a method to simulate the tri-axial dynamic deformation process of rock is proposed, and the corresponding method to determine the relative parameters is proposed as well. Finally, a practical example is employed to verify the feasibility of the presented model. The analytical results indicate that the proposed constitutive model can describe the characteristics of strain softening and reflect the influence of strain rate on the dynamic deformation process of rock.