The profile of cycloid-arc screw compressor rotors is not a smooth profile, and it has a tip on it. When designing the hob cutter is used for machining this kind of rotors, the profile of hob edge will appear separation. In this paper, the design theory of hob cutter for hobbing the no-symmetric cycloid-arc rotor with tip profile is researched, and the best way for design this kind of hob cutter with a separate edge is attained according to practical design, manufacture and test. Its results are shown that it is good practice to design the hob cutter and hob the cycloid-arc rotor. Thus, the machining method for hobbing screw compressor can enhance high productivity and machining accuracy.