Based on the mathematical model of the spindle motor YVF160L2 and the inverter, the space voltage vector modulation (SVM) and the direct torque control (DTC) were used for the highspeed precision roll grinder which grinding speed in more than 80 m/s. (SVMDTC), reducing the torque ripple during the operation of the spindle grinding wheel spindle; and using the model reference sensor to establish the speed observer to realize high speed precision roll grinding head spindle motor without speed sensing Closedloop control. The simulation results showed that the SVMDTC system based on the observation speed could effectively improve the fluctuation of the stator flux and output shaft torque during the operation of the spindle motor, and the control performance was improved obviously.