Abstract: Dragonfly is considered a high performance flyer in nature because of its wing structures. A computational fluid-dynamics-based study of a pleated wing section has been performed at low Reynolds numbers corresponding to the gliding flight of the dragonfly. The simulations demonstrate that the pleated wing produces high lift at wing roots, along the spanwise of the wing sections, the lift decreased gradually, until it becomes a small negative value at the wing tips, the phenomenon make the wing not bend along spanwise. In the cavities of the pleated wing, the resident vortexes make the wing have large stall angle. These ensure the stability of the dragonfly gliding flight.