Based on crash simulation the design of airbag system is optimized. In order to find the interaction between airbag design variables and injury criteria, the regression analysis is adopted. The solution process is systematically divided into five steps : 1) computer modeling for crash simulation, 2) decision of airbag design variables based on sensitivity analysis, 3) regression analysis of airbag system by design of experiment (DOE), 4) formulation of airbag design problem based on regression model, 5) optimization of the airbag system for minimum injury.