In this study, the aims were to analyze the cold forging process of the forward extrusion method and to investigate the design of the mechanism applied in the AA6061 heat sink part forging die set. First the CAE software, ”DEFORM-3D”, is not only used to analyze the stress and strain in the die as well as the situation of material flow during forging, but also analyze the forward extrusion process and the variables in extrusion die design are investigated. Then, the optimum variables according to the results of CAE simulation are used to design the actual die and are certified by the forging experiment using AA6061 aluminum alloy as the billet.