In view of the lack of local over-limit correction of the tool axes vector,a tool orientation smoothing method aiming to modify the kinematic performances of tool axes in local areas was proposed.Through the quaternion interpolation algorithm,the initial tool orientation planning on the whole machining track was conducted and the initial tool orientation under the workpiece coordinate frame was obtained.Taking the minimum change of rotation axis angle of machine tool as the goal and the kinematic performance limitation of machine tool as the constraint,the over-limit region was solved.For the over-limit region,local correction was performed with the target of minimum angular acceleration.An impeller blade machining experiment was performed to verify the proposed algorithm.The results show that through the proposed algorithm,over-limit can be avoided while maintaining the excellent processing characteristics of the original tool orientation,so the purpose of local optical rotation of the tool orientation can be achieved.