Abstract: The principle of feedrate control for multi-axis CNC machining of freeform surfaces is presented. The effective feedrate determination and control are implemented by synthesizing the following factors:a.constant feedrate of cutting point of cutter relative to part surface;b.the velocity and its changing rate of each movement axis not beyond the actuator limitation;c.smooth transition when the feedrate needs to change and during the period of machine start or stop. As a result, the machining quality and efficiency are improved effectively.