Abstract: The aerodynamic performance of a wind turbine is an important decision-making factor for technological transformation, and the aerodynamic parameters of the blades are a key source of data for accurately assessing the aerodynamic characteristics of the turbine. However, in actual engineering, the blade parameters of commercial turbines are often difficult to obtain due to confidentiality regulations or missing data of old models, resulting in a general inability to accurately calculate the aerodynamic characteristics of in-service turbines. A method of reconstructing aerodynamic characteristics for in-service wind turbines is proposed to address the difficulty of evaluating aerodynamic characteristics due to the lack of blade parameters of in-service wind turbines. Based on the terrestrial laser scanning technology, the blade geometry is obtained, and the distribution of airfoil shape, chord length and torsion angle along the blade spreading direction is fitted based on the wind turbine airfoil library. The airfoil aerodynamic characteristics are calculated by XFOIL software and Viterna extrapolation method. The model deviation caused by inaccurate pitch angle calibration is solved by using the consistency between the aerodynamic model of the turbine and the field operation data. Finally, a 2 MW commercial turbine is taken as an example for simulation verification, and the effectiveness of the proposed method is verified through comparative analysis with the field operation data and the turbine design curve.