This study would use the Taguchi method on the optimal processing parameter design of end-mell for high speed cutting SKD61 mold steel. The tool life is the major performance indexes of cutting process. The cutting processing paramaters of end-mill for high speed cutting are spindle speed, feed per tooth, radial depth of cut, axial depth of cut, helix angle, radial rake angle, radial relief angle, axial rake angle and axial relief angle. The optimal processing parameters could be evaluated by the Taguchi method. The results of confirmation experiments show that the Taguchi method can effectively use to evaluate the optimal processing parameter, then the tool life of high speed cutting for SKD61 mold steel can be improved effectively.