The study of fault mechanisms plays a crucial role in the field of fault diagnosis. The phenomenon of rolling element slippage is inevitable. In order to more accurately describe the phenomenon of rolling element slippage in the defective area, this paper employs the instantaneous center method and the theorem of three centers to represent the centerline velocity of the rolling element. Due to the change in linear velocity when the rolling element slips, the magnitude of the impact force is calculated according to the principle of collision. Finally, focusing on deep groove ball bearings as the research object, a fault dynamic model is established to simulate the slippage of the rolling element after being subjected to impact force in the defective area. The model is solved using the fourth-order Runge-Kutta method, and the results are simulated. Through experimental simulation analysis, the fault characteristic frequencies obtained from the proposed model are compared with theoretical values, with errors falling within the range of 1 to 2 Hz. Therefore, this provides preliminary validation of the correctness of the proposed model.