The wing structure of a WIG vehicle comprising left and right main wings, left and right downward wings, and a rudder unit. The left and right main wings protrude out from the central portions of left and right sides of the WIG vehicle. The panel of the main wing is flat and tapers successively toward the lateral edge, whereof the cross-section is airfoil-shaped and has the shape of a tadpole. The panel shaped left and right downward wings are connected with both ends of the left and right main wings without a joint and are formed heading downward to suppress vortex and guidance drag generated in both ends of the main wings. The rudder units are mounted on the rear surface of the left and right downward panels with a slight gap in order to compensate asymmetry between left and right lateral ends caused by movement under control of the fuselage driving unit of the WIG vehicle and to turn the fuselage left or right. Therefore, the wing structure of the WIG vehicle is capable of minimizing vortex and guidance drag generated in both ends of the left and right main wings by maximizing ground effect. Additionally, the wing structure has advantages for absorbing impact from the fuselage when taking off and landing and stabilizing horizontal disturbance of the fuselage because the left and right downward wings occupy much more volume than a winglet.