A numerical investigation is conducted to study the aerodynamic characteristic of the sinusoidal leading-edge (SLE) NACA0012 airfoil under the control of DBD plasma actuator. The results show that the application of SLE gives rise to strong spanwise pressure gradients, whereas the pressure discontinuity induced by the plasma actuator helps reduce the pressure gradient in the spanwise direction. At small stall angle of attack (AOA = 8°), the effect of the actuator on the airfoil is not obvious. With the AOA getting larger, the generation of stall vortex can be effectively suppressed by applying the excitation of the actuator under a steady continuous excitation mode applies voltage of 16 kV. while the delay of the separation point of vortices can also be observed obviously. And it can be proved that the aerodynamic performance of the airfoil is significantly improved under the control of DBD plasma actuator, especially at AOA = 12°–17°, At a 15° AOA, the lift-to-drag ratio reaches its peak, with a maximum increase of 36.1%.