Abstract: With the wind turbine enlarging, the length of the blade increasing and the stiffness decreasing, the aeroelastic vibration of the blade is aggravated during the operation of the wind turbine, which is prone to dynamic stall. Based on the analysis of the existing mainstream dynamic stall models, the German Institute of Aerodynamics and Gas Dynamics (IAG) dynamic stall model based on the integration of Beddoes-Leishman (B-L)and Snel model is used to simulate the dynamic stall characteristics of large blades, in order to obtain the unsteady aerodynamic load with small empirical parameter dependence and high simulation accuracy. At the same time, aiming at the problem that the wake separation point coefficient in the IAG model cannot fully describe the complete separation phenomenon, the wake separation point formula is improved to realize the calculation of the airfoil aerodynamic coefficient when the complete wake separation occurs. In this paper, S809 and S801 airfoils are taken as examples to verify the accuracy and stability of the improved IAG model by comparing with the physical experimental data and the B-L model analysis results. Then, taking the 10 MW wind turbine blade as the research object, the improved IAG model is integrated with the blade element momentum theory to analyze the aeroelastic coupling response at different positions of the blade under constant wind speed, and the unsteady aerodynamic characteristics of the blade dynamic stall region under random wind speed. The results show that the improved IAG model has good adaptability to different airfoils, and high calculation accuracy can be obtained without additional parameter calibration. The simulation analysis of the aerodynamic performance of large wind turbine blades shows that the model is easy to implement, the algorithm is stable, and has good computational efficiency.