At present,the rotation accuracy detection of the spindle of machine tools is a static test with the help of a standard ball under the no-load condition,which cannot reflect the actual rotation accuracy of the spindle in cutting conditions.Aiming at the problem that the spindle return error signal detected by the existing three-point method contains the system vibration signal,the vibration acceleration sensor is added on the basis of the traditional three-point method to measure the vibration acceleration of the system in real time.Moreover,a new three-point method including the separation of the system vibration signal is proposed,and the mathemati-cal model of rotation error detection considering the system vibration is established.The vibration displacement of the system and the absolute displacement of the sensor relative to the spindle are obtained and then the error separation technology is used for obtaining the actual rotation error of the spindle under cutting conditions.Fi-nally,a set of spindle rotation error detection device under cutting conditions is developed,and experimental re-search is carried out.The research results show that the method proposed in this paper can effectively improve the detection accuracy of spindle rotation error under cutting conditions.