Abstract: To investigate the static and dynamic performance of high-speed electric spindle,the finite element analysis method based on ANSYS was applied to determine static stiffness,natural frequencies and modal shapes of the spindle.By comparative analysis between the finite analysis and the modal experimental results,the error of the spindle's natural frequencies is very small and the modal shapes are basically identical.That shows that the boundary conditions and parameters' set are reasonable,and the results have practical value.By employing this finite element modal,the influence of the spindle span on the dynamics of the spindle was studied and the optimal range of the spindle span was determined.Results show that combining finite element analysis with modal experiment,the dynamic performance can be analyzed effectively and the structure optimization can be realized.