Abstract: In order to improve aerodynamic performance of wind turbine,taking bird coverts as the bionic objects,a bionic airfoil is proposed.In NACA0018 example,the bionic wing fins being arranged on the suction surface,analyzing the characteristics of fin flap homeostasis,and studying its effect on the aerodynamic performance of the airfoil,the flow control mechanism is revealed.The results show that when the wings are in aerodynamic balance fin angle,the maximum lift coefficient is increased about 5.69%,160 angle of attack has most obvious effect which enhances the maximum lift coefficient about 16.02%.When the control angle of the fins is in the best,the wing maximum lift coefficient is increased about 12.76%,the lift coefficient is enhanced about 23.79% when the angle of attack is 16°.The wing fin in optimal control angle leads to the pressure reduction of airfoil upstream surface,and the pressure increase relatively on the downstream surface,the pressure surface exhibits slightly overall reduction phenomenon.According to the relationship between the aerodynamic moment coefficient of the flap and the lifting angle,and the aerodynamic moment coefficient when the flap is at the optimal control effect point,a method of adding the corresponding external moment at the hinge point of the flap is proposed to balance the optimal control of the flap.The airfoil is optimal at the moment of aerodynamic torque balance.