The paint repairing robot for cars needs to face vehicles in different sizes and adapt to a variety of modeling surfaces and colors. This highly adaptive requirement makes the design of the paint repairing robot far more difficult in target tracking, path planning, motion space, and other aspects than the painting robot in the automotive manufactory. Therefore, the painting path re-planning is necessary. First, a large amount of point cloud data is segmented by parts, and then the eight-neighborhood method is used to calculate the contour of the closed surface. Finally, the grating path is generated on the surface by the slicing method, and the critical path of each surface is formed. The eight-axis truss robot system is designed and manufactured, and the path planning of the eight-axis linkage is generated by the ant colony algorithm. Subsequently, the generated path and trapezoidal curve acceleration are sent to the PLC-based motion control program through the ADS protocol of the Beckhoff controller to complete the linkage and collaborative paint repairing movement of each joint axis. The experimental results show that the system can automatically control the axis of the robot tool to align the arbitrary surface with the normal vector for different vehicles and drive the eight axes to track the surface motion smoothly. The system can also be widely applied to the robot machining of various surfaces.