Abstract: The blunt trailing edge wind turbine airfoil has the advantages of high structural strength and insensitive to surface contamination, but its larger drag coefficient makes the aerodynamic characteristics of the blunt trailing edge wind turbine airfoil unsatisfactory. The circulation control method is implemented on a blunt trailing edge wind turbine airfoil in order to improve the aerodynamic characteristics of the blunt trailing edge wind turbine airfoil, and weaken the strength of the shed vortex. The circulation control on a blunt trailing edge wind turbine airfoil is investigated using numerical simulation methods. The effectiveness of the circulation control method in increasing lift and reducing drag is researched. The variation of lift and drag coefficients with the jet momentum coefficient is studied, and the aerodynamic figure of merit and the control efficiency of the circulation control with different jet momentum coefficients is analyzed. The results show that the circulation control can significantly enhance the lift coefficient of the blunt trailing edge airfoil, and effectively reduce the drag coefficient of the airfoil; the lift coefficient of the airfoil increases with the jet momentum coefficient, and two typical control regimes, namely, separation control and super-circulation control, are observed; the power coefficient of jet increases with increasing jet momentum coefficient, and growth rate gradually increases; the output power of blade also increases with increasing jet momentum coefficient, but the growth rate decreases gradually. It is demonstrated that the circulation control method can significantly improve the aerodynamic characteristics and power output characteristics of blunt trailing edge wind turbine airfoils, and it has a good application prospect in large wind turbine flow control.