Due to the deficiency of existing cold extrusion process of spherical hinge shell of automotive steering linkage, [JP2]the needed fillets could not be achieved. Therefore, the numerical simulation was performed in order to optimize the preform shape using finite element method. Based on Deform\|3D platform, different final extrusion simulations were executed for spherical hinge shell preforms with different shape dimensional parameters. Three optimization schemes were designed. The bottom shape was designed to truncated cone\|shape in optimization scheme 1; then it was changed to square in optimization scheme 2; based on optimization scheme 2, four edges were filleted in optimization scheme 3.The result of numerical simulation indicates that fillets can be achieved freely and precisely using preform specimens, whose four edges can be filleted and square bottom shape is designed. Then the die structure was modified according to the simulated result.