This paper presents the development of high power and economical lap belt pretensioner. Lap belt pretensioner could be fitted to increase the occupant pelvis restraint with the seat and limit the pelvis forward displacement. Keeping an occupant from moving forward relative to the vehicle interior is crucial to minimizing injury. The aim of this work is cost and weight reduction and localization of lap belt pretensioner using Design For Six Sigma(DFSS). In addition, its performance should be above same the other lap belt pretensioner. To achieve the aim, orthogonal array is used. DFSS evaluates the influence and the interactions of selected control factors of lap belt pretensioner through a limited number of experiments and the optimized lap belt pretensioner system was verified.