The invention belongs to the technical field of complex surface part high-precision and high-efficiency milling, and relates a tool axis vector fairing method based on the kinematics characteristics of a swivel feeding shaft of a machine tool. The method comprises the steps: taking equal residual height as a constraint to generate a processing tool path according to the geometric features of a curved surface; building a coordinate conversion relation between a workpiece coordinate system and a machine tool coordinate system, converting a tool axis sequence corresponding to a tool contact pointinto a corner sequence of the swivel feeding shaft of the machine tool, and determining a to-be-optimized section according to the angle changes of the swivel feeding shaft of the machine tool; calculating tool axis vector coordinates corresponding to the tool contact point in the to-be-optimized section based on a quaternion method, carrying out the fairing of a corner curve of the swivel feeding shaft of the machine tool through the least square fitting method, and carrying out the interference checking and adjustment of the optimized cut axis vector. The method effectively reduces the motion abrupt changes of the swivel feeding shaft of the machine tool in a machining process, achieves the steady machining, and improves the surface machining quality.