This paper investigates the control of leading-edge flow separation over an airfoil using a dielectric-barrier discharge plasma actuator. A chord-based Reynolds number and an angle of attack are 2.6 × 105 and 18.8 deg, respectively. The flow around the stalled airfoil is computed by using large-eddy simulations. The body-force distribution-based plasma actuator model is adopted and set near the leading edge of the airfoil. Effects of a nondimensional burst frequency with a constant duty cycle onthe performance of flow control are studied. It isfound that, for the cases of the nondimensional burst frequencies 5, 10, 25, and 50, lift-to-drag ratios increase in comparison with that in the cases of the burst frequencies 1 and 100 and without the control. Controlled flow separates near the 30% chord from the leading edge due to adverse pressure gradient associated with the angleofattack. Mechanisms of suppression of the leading-edge flow separation in those cases are discussed.