The purpose of this study is to find optimum machining conditions to improve the quality of die using CAD/CAM system(Power Shape & Power Mill). In this paper, at first, create the tool path and generate NC codes using Power Mill. And then we cut a material by CNC machine(NBS-2025). Finally, we measure the surface roughness using surface roughness measuring instrument(TR-200S). Through this study, the optimal machining condition can be obtained. Also this result will be reflected to die design and machining.