Driven largely by the never ending quest for weight reduction to decrease fuel consumption and emission, the automotive industry is predicting significant growth in the use of aluminum alloys. Generally, cold chamber type die casting process is utilized for aluminum alloys. In order to comply with the growing demand for life cycle environmental effect, life cycle assessment (LCA) was carried out for producing A356 aluminum alloy by cold chamber type die casting process, based on what has been experienced as needed for LCA study. The main emphasis of this study is to evlauate the effect of trial of improving die casting process and product quality on the environmental value obtained by LCA. Also the results will be compared by the trial of life cycle improvement. In LCA, the process evaluated was based on yields of finished parts relative to the metal input. This is important both in environmental point of view and in commercial point of view, because the environmental data are sensitive to the design of the cast part and the efficiency of the die casting operation.