Magnesium alloys are very attractive materials for applying to the development of automobile parts or electric goods where a lightweight and a higher strength need. Due to higher ratio of strength vs. weight and stiffness vs. weight, various magnesium alloys are well applied in much weight saving design applications though an extrusion or a die-casting process. However, for the requisites of higher strength and weight savings, some new fabrication processes has been and it can be realized though the aid of the injection molding technology. To obtain the parametric data based upon the injection molding process, various experiments were executed for AZ91D magnesium alloy. This research proposes the optimum condition of an injection temperature, the first and the second pressure. The process was lined-up successfully often changing the injection unit and the hydraulic unit from the conventional plastic injection machine.