Abstract: The three-dimensional fluctuating wind fields of downburst was established by the theoretical analytical model combined with IECKAI spectrum,which are used as the input condition of OpenFAST code. The aerodynamic loads of rotor and tower are calculated and analyzed. The results show that when the wind shear across the rotor plane is negative due to the height change of horizontal maximum wind speed,the thrust and torque of the rotor are minimum. When the height of the horizontal maximum wind speed changes from the bottom to the top of the rotor,compared with the minimum value,the maximum value of the root mean square of the rotor lateral force,longitudinal force,tilt moment,and yaw moment coefficients increased by 29.01%,30.00%,38.79%,and 38.93%,respectively,and the maximum value of the average aerodynamic drag coefficient in the fore-aft direction of the tower increases by 5.6times at the section position 19% away from the tower foundation.