In order to improve productivity and product quality and reduce cost, over the past many years, producers made great efforts to find the new method of chamfering. One of the methods is the chamfer milling cutter, on the milling machine tool. This method is suited for medium and small batch production. The tool life is long, the machining quality is stable. In this thesis, the principle of meshing between gear and the rake is applied. The chamfer miller design principle and calculation method is put forward.