Abstract: This paper considers the wingbody shape with two different types of winglets (the blended winglet and shark winglet) by discretized Reynolds average Navier-Stokes equation and the aero-structure coupled equation. The impact of the different heights of the winglet on the lift-drag ratio, the displacement of the wing pressure center, the weight and the flutter character is studied. The results show that the weight increase of the aircraft structure is smaller than the weight increase of effective loads and that the flutter velocity decrease is adjustable within the safety range. Therefore, it is suggested that the selection of the winglet height should have a priority over the lift-drag ratio character during the trade off between aero and weight & flutter in order to have a good drag reduction.