Taking the high-speed grinding motorized spindle as the research object,the expression form and classification of motorized spindle rotation error were analyzed.The error separation model was established,the method of subtracting the minimum trough value from the maximum peak value was proposed for error separation,and the motion models of radial error,tilt error and axial error were established.The radial error was analyzed by using the least square average algorithm,and the tilt error was obtained based on the radial error trajectory analysis.Combined with the signal analysis methods in time domain and frequency domain,the axial error was analyzed.Based on the measurement system composed of double standard balls,multiple high-precision capacitive displacement sensors and temperature sensors,the dynamic rotation error measurement experiment was carried out in a domestic grinding motorized spindle.The results show that with the increase of rotating speed,the error of grinding motorized spindle gradually decreases and tends to be stable; when the error is the smallest,the radial error is 7.5 μm,axial error is 6.02 μm,tilt error is 25.91 μrad；during the long-term operation of motorized spindle,the change of rotation accuracy is not obvious with the increase of temperature,but there will be thermal offset.