Increasing the fuel economy has been an inevitable issue for the development of new cars, and one of the important measures to improve the fuel economy is to decrease the vehicle weight. In order to obtain this goal, the researches about lighter, stronger and the well impact absorbing bumper impact beam have been studied without sacrificing bumper safety. In this study, the overall weight reduction possibility of rear bumper impact beam could be examined based on the variation of frontal, offset and corner impact crash capability by substituting a ultra high strength steel material (boron steel ) having tensile strength of 1.5 GPa grade instead of conventional steels. In addition, the section variations (open section, closed section, open section with 5 stays) of the bumper impact beam structure were examined carefully. It could be reached that this analysis could be well established and be contributed for design guide and the optimum design conditions of the automotive rear bumper impact beam development.