The structures of existing wings had holes for light weight and plates and frames were fixed with rivets or screws, thus, there were difficulties and limits in light weight. Welding process generates distortion and residual stress in the welding due to rapid heating and cooling. Welding distortion and residual in the welded structure result in many troubles such as dimensional inaccuracies in assembling and safety problem during service. The accurate prediction of welding residual stress is thus very important to improve the quality of welding and find the way to reduce itself. In this study, an improvement was made in current joint methods through EB welding and laser welding for light weight of wings and welding strength was measured through strength test. In addition, finite element analysis was performed for welding process so as to induce optimum welding condition.