Based on the principles of Laser Doppler Displacement Measurement of rotational axis

the measurement and compensation of roational axis positioning error for CNC spiral bevel gear grinding machine are studied.The rotational axis positioning error of homemade CNC spiral bevel gear grinding machine（YK2050） is measured by using laser interferometer（MCV2002 and RT-100 rotator）.Based on software error compensation theory

the positioning error of rotational axis is compensated in numerical control system（Siemens840D） by modifying NC data of the system.The result of measurement and compensation reveals that this error compensation method and technique can greatly improve the positioning accuracy of rotational axis.