Abstract: In consideration of the constraints of shape stealth, a under-wing lift augmenter was designed for carrier-based fly-wing UAV wings. Regarding future anti-stealth technology, i.e., wake flow detection, the flow mechanism around the lift augmenter was analyzed, and the wake flow can be weakened by the lift augmenter, so as to avoid the detection of wake-detection radar. The results show that this lift augmenter can effectively increase aerodynamic lift weaken induced drag, and improve lift-drag ratio. Moreover, the augmenter has the effect on weakening the wake flow. Based on mechanism analysis, the current configuration, compared with conventional aircraft with winglet, has the advantages of drag reduction, lift increment, and weakened wake flow at large angle of attack.