Abstract: The induced drag reduction is an important problem for the commercial transport aircrafts and the high altitude long endurance unmanned aerial vehicles. An aeroelastic model is established based on the lifting-line theory. The induced drag is reduced by deflecting full-span leading- and trailing-edge control surfaces. The aspect ratio of the rigid wing and the elastic wing are 8. When their taper ratio(TR) is 0.8, the results including induced drag distributions etc. show that the above method is efficient. For the rigid wings which have the same area and different taper ratios, the ratio of the lift to the induced drag is best when their TR is about 0.4. For elastic wings whose stiffness distributes uniformly, the ratio of the lift to the induced drag is best when their TR is about 0.2. The deflection of the control surfaces reduces the displacement of the elastic wing tip. The results give out the reference to the drag reduction using a finite number of control sufaces in engineering application.