Blade disk rotor system is a typical structure of industrial equipments such as aeroengines and gas turbines. The research on the response characteristics and mechanism of the system under the coupling effects of aerodynamic force and blade crack is of great significance to the interpretation of vibration phenomena and diagnosis of faults. From the numerical solution based response characteristic analysis to the kinematics and dynamics based essential response mechanism revealing, from the model based special case study to the Number Theory based general law establishing, in this paper, the response mechanism of blade disk rotor system under the coupling effects of crack and aerodynamic force is studied comprehensively and deeply. Firstly, a simplified dynamic model of 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 vibration response under the actions of aerodynamic force and blade crack 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 are revealed. Finally, based on Number Theory, the response characteristics and mechanism of typical structures are summarized, and the general laws of responses with general structural forms are established.