Abstract: To quantify the influence of manufacturing error of wind turbine blade on the aerodynamic performance,an uncertain aerodynamic response model of wind turbine was established based on the interval analysis method and the blade element momentum theory. The influences of uncertain manufacturing error on power and thrust were quantified for the NREL Phase VI S809 wind turbine.The sensitivity analysis was conducted based on the range analysis and the sensitive positions of uncertainty were obtained. Results show that,the effect of blade twist angle error on performance is more significant than the chord length error. When the chord length error and the twist angle error is ± 0.02c and ±0.6°,respectively,the maximum relative fluctuation of power and thrust is 3.26% and 8.09%respectively. The sensitive position of chord length error influence is located at the blade root,while the sensitive position of twist angle error influence is on the blade tip area. The performance deviation can be significantly reduced by applying strict quality parameter control on these positions.