Abstract: The effects of trailing flap length, deflection angle and angle of attack on the load reduction characteristics of airfoil were studied, and the influence mechanism was analyzed. Results show that the cooperative control of the pitch and the trailing flap can effectively realize the load reduction in the swing direction. The larger the length of the trailing flap, the smaller the trailing edge deflection angle. The farther away from the critical value of the angle of attack, the better the load reduction performance. The increase of the deflection angle will lead to the forward movement of the critical angle of attack. The tail edge control is preferred under the positive deflection angle and the large angle of attack, and the pitch control is preferred in other cases. The load reduction characteristics are closely related to the fluid distribution of the airfoil and wing slots, and the smaller the pressure difference, the better the load reduction performance.