The application of plasma actuators for flow control is one of the most popular researches nowadays. By using numerical simulation, this paper mainly studied two things: the method of simulating the effect of plasma actuators on flow fields; the plasma control of airfoil separated flow at large angles of attack. In this paper, a simplified model for plasma actuators is presented using FLUENT UDF to numerically simulate the plasma control of NACA0015 airfoil at large angles of attack. The results show that DBD plasma actuators can delay flow separation, increase the lift, and decrease the drag of the airfoil. Based on the analysis of numerical results, this paper also discusses the effect of the location, number, and strength of plasma actuators on flow separation.