Abstract: Saucer-shaped aircraft is a new type aircraft configuration with blended fuselage and wing. Through the method of changing centre of gravity, flight stability was acquired and validated in the flight test. A type of fin-shaped wing-tip winglet applied to this aircraft to reduce induced drag was presented. Compared to the original type without winglet, the lift to drag ratio of new model can be improved by 70% at the speed of 30m/s in wind tunnel. The results of tunnel experiments were verified successful in test flights. Not only its load was increased but also its aerodynamic performance was good. In order to realize its aerodynamical characteristics, computational investigation was performed to the flow field. By analyzing the results, wingtip vortex had important influence to its performance.