The feed system is one of the important components of the vertical machining center, and its vibration characteristics have an important influence on the processing quality of the product. Taking a large vertical machining center as the research object, the rigidflexible coupling model of the ball screw feed system was established, the dynamic characteristics of the screw feed system were analyzed, the amplitude variation rule of the screw in different speed range was studied, and the static and dynamic mechanical responses of ball screw were analyzed. The simulation results show that the large vertical machine feed system can meet the design requirements.The research result provides a theoretical basis for the optimization of large vertical machine feed system.