Abstract: In order to further analyze the aerodynamic characteristics of the large wind turbine blades,the yaw load is equivalent to the pitching motion. Based on the k-ω SST turbulence model with transition correction. The effects of the oscillating at the same frequency but with different phase difference and different reduced frequency under the action of the compound motion of the pitch,flapwise and edgewise at Reynolds number of 10~6 on the aerodynamic performance of the NREL S809 airfoil were studied. The results show that the flapwise velocity near the dynamic stall angle has a great influence on the aerodynamic coefficient of the airfoil. The airfoil pitch can significantly increase or suppress the dynamic stall angle when it has different phase from the flapwise and edgewise motions. The change in the reduced frequency can greatly affect the aerodynamic performance of the compound motion in different phases and the dynamic load is more sensitive to the phase difference than that of the reduced frequency in the compound motion.