Abstract: How to accurately predict the aerodynamic performance of wind turbine airfoils is a key problem to be solved for well-designed wind turbine blades. The research object is NREL S810 which is a special airfoil for large wind turbine, and pressure measurement method of wind tunnel is adopted. The influences of turbulence intensity on aerodynamic performance of airfoil at different Reynolds numbers are analyzed. The results show that the lift coefficient and drag coefficient of the airfoil increase at first and then decrease with the increase of turbulence intensity. When the turbulence intensity is 4.6%, they increase to the maximum and then begin to decrease. When the turbulence intensity is less than 11%, the lift and drag coefficients increase with the increase of Reynolds number. When the turbulence intensity increases to more than 11%, the lift and drag coefficients decrease with the increase of Reynolds number. With the increase of Reynolds number, the maximum lift-drag ratio increases first and then decreases, and the angle of attack corresponding to the maximum lift-drag ratio moves forward first and then moves back.