Considered structure vibration of angular contact ball bearing, the elastic deformation of rolling elements in form of matrix or vector was defined so as to keep structural integrity and get clear notation, in this way, the elastic deformation of every rolling element could be calculated easily. Combining Hertz contact theory and Lagrange mechanics theory, a 5-DOF dynamic model was built. By using this model, the relationship between the frequency of structure and the preload, the contact angle and ball position was discussed. Eexperimental results proved that the error of the dynamic equation was less than 15%, which met the requirement of engineering calculations.