Abstract: A discrete vortex method based on the slender body theory is proposed by setting vortex-elements on the wing and point vortices on the free vortex-sheets to simulate the flow pattern of the rolling-up of vortices separated from the leading-and trailing-edges of a slender wing. The method is particularly convenient for complex configurations, because the computation is needed only in the physical plane without the use. of conforrnal mapping as useally done previously. A 74 swept delta wing and its modification equipped with vortex-and apex-flaps were selected to calculate their separated vortex flow patterns. The computational results appears satisfactory in comparison with the experiments.