Abstract: Wind turbine aerodynamics has been one of the hottest research topics at home and abroad. At present, most relevant researches are based on deterministic working conditions. However, since wind turbine works in the complex environment of natural flow in the atmosphere all the year round, wind speed fluctuates and changes randomly, the power output of wind turbine is uncertain. The uncertainty of wind power system brings great challenges to the stability of national grid. It is important to study the aerodynamics of wind turbine under uncertain wind speed conditions. In order to reveal the influence mechanism of uncertainty on wind turbine flow field and to determine its influence on loads, this paper proposes an uncertain aerodynamic analysis method for wind turbine. Based on the blade element momentum theory and the non-intrusive probabilistic collocation, the uncertainty aerodynamic response model of horizontal axis wind turbine was established. Taking the NREL Phase VI S809 wind turbine rotor as the research object, the random output response information of wind turbine was extracted, and the influence of uncertain wind speed on turbine power, thrust, blade flapwise bending moment and edgewise moment of wind turbine were quantified. Based on the uncertain analysis of the flow induction factors in the length direction of the blade, the uncertainty propagation mechanism in the wind turbine field was revealed, which provides a reference for the wind power system design and application. Results show that, the wind speed fluctuation has a significant influence on the wind turbine power and aerodynamic forces. The standard deviation of random Gaussian wind speed range increases from 0.05 to 0.15 times average speed, the maximum fluctuation ranges of power and thrust increase from 13.34% and 8.00% to 35.11% and 22.02%, respectively; the maximum fluctuation ranges of blade flapwise bending moment and edgewise moment increase from 7.20% and 12.84% to 19.90% and 33.49% respectively. The uncertainty of the incoming wind speed leads to the obvious fluctuation of the local flow at the blade root sections, which indicates that flow control techniques can be applied in this part of the blade to reduce the sensitivity to the uncertainty of wind speed.