The purpose of this study is to analyze the problems of current rules and regulations on the source selection for weapon system in defense acquisition project and suggest several techniques to ensure objectivity and fairness. As an application example, Helicopter source selection was presented. It was analyzed and compared through technique application and strength and weakness analysis of AHP, PROMETHEE and Attribute Transformation. The decision making techniques which make all conditions satisfactory in all situations are nonexistent. Thus, it is estimated that we can maintain the objectivity in the source selection of weapon systems by applying suitable decision making techniques in accordance with the patterns of evaluation item.