The measurements for mechanical properties of testing bar were conducted.The results shows that tensile strength of major flat bars are slightly higher than that of round bar at the same processing parameters.The processing parameters have the significant effects on the mechanical properties for a identical materials and die casting components.The hearted part microstructure has the obvious effects on the tensile strength while chilling surface microstructure has the slight effect.The conventional defects occurred in heart part lower more affects the mechanical properties than in surface.