To proceed an efficient acquisition program, a variety of factors such as acquirement of excellent weapon system, research and development of defense technology for independent national defense and efficient obtainments are needed to be considered. But present evaluation system of weapon is not enough to include them all. Therefore this study aims to design weapon evaluation system to overcome the cognitive error of decision makers and to cope with the complexity and uncertainty in national acquisition field. To accomplish the goal, the researchers derive 4 factors (compatibility of hierarchy, extensibility, compromise between cost and non-cost factors and aggregation of evaluation criteria and group) based on AHP. And the research intends to present rational weapon evaluation structure which can include national security environment to analysis and guarantee the objective setting of weights through empirical tests.