Abstract: A bi-objective(BO) optimization method was proposed for civil transport wing design.The thickness and twist angle of wing sections along wingspan were chosen as the optimal design factors, the two goals were the lift-to-drag ratio and wing's volume at fixed lift coefficient. Navier-Stokes(N-S) equations were used as flow field solver and Powell method was used as optimization design tool,the Lockheed-AFSOR Wing A and some civil transport's wing were computed as cases.Cases on Wing A at 0.6217 Mach number condition showed that the BO optimization results were better than the single one. Case on civil transport wing at the cruise Mach number of 0.78 and the lift coefficient of 0.48 also showed that the BO optimization method could lead to higher lift-to-drag ratio and bigger wing volume. Comparing with the original wing, the BO optimal wing's maximum thickness-to-chord ratio was bigger at the root and smaller at the tip,and the absolute value of twist angles were all smaller. The BO optimization design method is better than the common single objective optimization design method,and could provide some value for civil transport engineering design.