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.