Joined-wing aircraft is one of the solutions to cope with rapid growth of air traffic flows by increasing the capacity of both air and ground. Since the joined-wing aircraft has many advantages of higher aerodynamic efficiency, shorter take-off distance, resistance to bending moment, etc., numerous research have been carried out so far to investigate its flight characteristics especially in the United States. In our study, the joined wing configuration is conceptually designed and analyzed through an initial sizing process followed by a series of detailed sub-disciplinary analyses of aerodynamics, aero-elastics, and stability & controls. Based on the design results, a model UAV of the designed joined-wing aircraft is also constructed and test-flown to verify the feasibility of the initial design and to validate the sub-disciplinary analyses results. A test-flight of the joined-wing UAV was very successful, which indicates that our design process was valid and sub-disciplinary analyses were accurate.