Abstract:As to the long span ball screw in large and high-speed machine tool, because long stroke and the ratio of length to diameter was too large, a series of problems in operation, such as large deflection and jittering were resulted, which seriously affected the dynamic capability of machine tool. According to the structure of screw and the differences of drive mode of ball screw, the vibration mode of long screw and its effect on the machine tool’s critical speed and transmission accuracy were analyzed. Through the ANSYS Workbench dynamic analysis module, the modal and vibration response of ball screw were analyzed. Aimed at the problems occurred, the corresponding technical solutions are put forward. The research results provide reference basis for solving problems in long span ball screw’s engineering application.