Abstract: The performance of electrospindle levitated with active magnetic bearing is verified by actual grinding process．Using the floating point DSP(TMS320C32) as microprocessor，a digital control system for the electrospindle is developed．The mechanical feature of grinding force acted on the rotor of spindle is considered when the spindle is used to grind the internal surface of rolling bearing inner ring，the control parameters is determined according to the analysis above．The electrospindle is well suspended in a stable static state and rotate at 60 kr/min with vibration amplitude less than 8 μm．Its stiffness can be up to 22～58 MN/m．The results from grinding process with the spindle mounted on a precision grinding ma-chine show that the accuracy of finished surface of workpiece can fulfil the request quality of machining. The fine grinding efficiency approaches the standard for industrial applications．

Key words: Active magnetic bearing, Eelectrospindle, Grinding