In order to improve the control accuracy of machine tool,a method of analyzing spindle rotation accuracy was designed,which could accurately predict cutting force correction.In order to verify the accuracy of rotary accuracy prediction,a set of spindle rotary accuracy analysis system without standard ball was established,the spindle rotation precision test could be carried out according to the specific cutting conditions.The results show that with the change of feed rate and cutting depth,regular synchronization error is formed.The cutting depth is the most affected by the synchronization error factor,and the feed speed is the second.Under the influence of cutting load,the spindle rotation accuracy changes significantly,and the synchronization error is positively correlated with the cutting load.Under variable feed and variable cutting width,the test results are similar to the simulation results,maximum error is 0.2 μm.The roundness error obtained with the condition of cutting width 12 mm and feed speed 1 200 mm/min is consistent with the roundness error at 100 r/min idling.