Abstract: To solve the problem of inaccurate prediction of wear distribution per tooth caused by continuous change of tool contact points in the processing of multi-axis machine tool, a wear overlap distribution model with tool run-out was established. The element wear distribution per tooth model was developed by tool geometry model and worn cutting edge trajectory model. The wear overlap distribution per tooth model with actual cutting depth and contact point of each flute was proposed by the milling mechanism per tooth and tool run-out. A case study was carried out to validate the prediction accuracy of the proposed model. The comparison results show that there is a good agreement between simulation and experiment results.