Abstract: The ability to model the unsteady aerodynamic effect with high accuracy and efficiency is crucial for practical applications of airfoil with trailing edge flaps, Sush as vibration and noise reduction, perfarmance impraement, and main operation. Firstly, the unsteady aerodynamic characteristics of an airfoil with trailing edge flap were calculated using CFD method. The correctness of the results was verified by comparing with the experimental data of wind tunnel. Furthermore, combined the fuzzy logic approach and CFD calculation results and established an efficient model for unsteady aerodynamics of an airfoil with trailing edge flap. The parameter identification and structure identification were employed by using the Newton gradient-descent method and search forward algorithm, respectively. Taking SA349 helicopter rotor airfoil with flaps as reference, the prediction results of unsteady aerodynamics flap with 1Ω and 2Ω oscillations by fuzzy logic model and CFD were compared. The results show that predicted unsteady aerodynamics are in good agreement with the CFD calculation results, and shows superior computational efficiency, validating the combined approach has high calculation effectiveness and accuracy.