The coupled thermal error between the spindle and feed shaft could actrually reduce the accuracy of workpieces in prcessing. For the problem, we developed the conprehensive thermal error model of spindle and feed shaft, with the expansion of workpieces, and verified it. The mutual effection among spindle, feed shaft and workpiece were comprehensively analyzed, and the multivariable linear regression model was developed among them. The results show that the comprehensive model could be consistent with lathe's processing situation and increase the processing accuracy effectively. The prediction accuracy for the spindle is more than 85%, and 70% for feed shaft. The error rang in processing is declined from 15 μm to 5 μm.