The special shaped spiral rod can not be machined on a universal CNC lathe or a milling machine because its pitch and the bottom diameter vary with the angle. In this paper, a new type special CNC milling machine for processing long special shaped spiral rod is designed with the FANUC 0i-MC CNC system with the horizontal structure. The CNC milling machine is of three-axis linkage. The rotation of the workpiece is driven by axis c, and the milling feed is provided by the Alternating Current (AC) servo motor on the axes x and z. The AC frequency conversion stepless adjustment is adopted to control the rotation speed of the milling spindle. It is shown that the new machine has a wide range of practical engineering applications in view of improving the productivity and machining quality for processing special shaped spiral rod, and extending the functions of CNC milling machines.