Abstract: To further improve the lift efficiency of the attached flap on the airfoil, this paper proposed a curved airfoil trailing edge attached flap model based on the special motion form of the fluke when the dolphin moves forward. Firstly, based on the published literature, the correctness of the SST k-ω Turbulence model used in the numerical simulation of two-dimensional incompressible RANS and the grid distribution used in the numerical simulation of airfoil flow were described. Then, the effectiveness of split flap and bionic curved flap was verified, and these lift principles of the two kinds of flaps were analyzed respectively. Finally, the lift characteristics and drag variation principle of the bionic curved flap and airfoil under different Reynolds numbers were studied by changing the incoming flow Reynolds number. The results show that: on the basis of ordinary split flap and airfoil as a whole, the lift coefficient of the proposed bionic curved flap model and airfoil as a whole increases by 10.96%, and the lift-to-drag ratio increases by 9.39%; the Reynolds number has a positive correlation with the lift coefficient growth rate of the attached bionic curved flap and airfoil as a whole, and a negative correlation with the lift-to-drag ratio growth rate of the attached curved split flap and airfoil as a whole. The results of this paper can provide a reference for the design of lift augmentation of the attached flap near the trailing edge of the airfoil.