Rolling bearings are vital components in rotating machinery.Its failure will bring operational failures to the entire machinery.In order to more accurately reveal the mechanism of the vibration response of the surface defect bearing,considering the influence of the unbalanced force and the disturbing force generated by the operation of the rolling bearing,based on the Hertzian contact theory,combined with elastic mechanics,bearing kinematics and geometry,4-DOF dynamic model of deep groove ball bearings were established.In order to better describe the position of the bearing defect,the defective part is mathematically treated.The model regards the defective part as a rectangle,and describes the transmission of the shafting-inner ring-outer ring-bearing seat from the angle of the actual movement of the bearing.process.Taking the SKF6205-RS deep groove ball bearing as the modeling object,the Lagrange equation of the dynamics is solved by the method of the fourth-order Runge-Kutta variable step size,and the vibration response time domain signal and frequency domain signal of the outer ring defect are obtained.Compared with the bearing experimental results of Case Western Reserve University,the feasibility and accuracy of the model were verified.