High speeds and acceleration create high reactive forces between the moving mass and the stationary bodies of the ball screw feed drive system and excite the structure which causes undesired vibrations. Therefore, it is necessary to have an accurate dynamic model of the feed drive system for machine design and controller tuning. An optimized dynamic modelling and simulation method of a ball screw feed drive was presented based on the lumped mass model. The mass and the rigidity of the ball screw feed drive basis were considered in this new model and the calculation method of the equivalent parameters was optimized. Simulative and experimental examinations were conducted based on an X -axial ball screw feed drive system on a MAG machining center and the presented method was proved to be accurate because of the same eigenfrequency number and the limited error (less than 5%) between the simulated and measured eigenfrequencies of the ball screw feed drive system. Based on this model the vibration characteristic of a ball screw feed drive system was studied. The simulation results showed that the natural frequency change caused by the nut position change affected the stability of the servo system, and the backlash of feed drive system encouraged the components to produce high-frequency vibration and made the servo system unstable.