Toward improving a wing performance at cruise conditions, large-eddy simulations (LESs) of the flows controlled by a DBD plasma actuator on a NACA0015 airfoil are performed. The Reynolds number is set to be 63,000, and the angle of attack is set to be from 2 to 8 degree, respectively. The DBD plasma actuator is installed at 5% of the chord length from the leading edge on the airfoil surface of the suction side. The actuator is driven by a burst mode actuation which is one of an effective strategy for separation flow control. At the high angle of attacks (6 and 8 deg), the actuator achieves better flow control and get higher lift-drag ratio than Ishii airfoil which has a good aerodynamic performance at low Reynolds number conditions such as the present Reynolds number owing to drag reduction. The actuator generates the spanwise vortices shed from the leading edge and promotes a flow reattachment in these cases. As a result of the promotion of the flow reattachment, the separation bubble becomes shorter and a pressure recovery occurs at the location closer to the leading edge compared with the case without the actuator. This pressure recovery is similar to the cases of the Ishii airfoil and contributes to the improvement of the lift-drag ratio.