Development of lightweight automobile is a substantial alternative measure for the global environmental regulations change. For developing lightweight automobile, the lightweight materials such as magnesium, aluminum and engineering plastic have replaced conventional steel in materials and the manufacturing process for lightweight materials are suggested and developed. But, there remains an issue for ensure safety and equivalent performance compared to existing parts. Especially, a beam-type body parts directly related to passenger safety are very difficult for lightweight since there remains an important issue of absorbing and dispersing sufficient energy in the event of a vehicle collision. In this study, to maximize the effect of lightweight and ensure equal performance developed bumper beam and door impact beam which applied thermoplastic fiber composite material and optimal structure design for application closed surface and new method.