The important role of a dynamic model is to study the response characteristics of a system under different parameters or fault states. These response characteristics can be used in many aspects, such as condition monitoring and fault diagnosis. Usually, the response characteristics can be obtained through numerical analysis, but we do not know why such characteristics appear, which hinders our understanding and utilization of vibration. The innovation of this paper is to reasonably explain why such response characteristics appear. First, a simplified dynamic model of a typical blade disk rotor system is constructed by using the classical continuous parameter modeling method. Based on the dynamic model, for two structural forms of moving and stationary blades, the typical characteristics of the vibration response under the actions of aerodynamic force and blade cracks are analyzed by means of numerical solution. Then, from the perspective of kinematics and dynamics, the internal mechanism between the vibration responses and the excitations is revealed. Finally, based on Number Theory, the response characteristics and mechanisms of typical structures are summarized, and the general laws of responses with general structural forms are established.