Abstract: A method using second generation of Low-Order Panel Method coupled with Pseudo Implicit Free Wake Calculation to calculate the rotors aerodynamic load is presented in this thesis. The threedimensional geometric property of blade is considered in the calculation. Triangular and quadrilateral panel is used to reconstruct the rotor blade. The full span wake model is used in this method, which contains three cycles of free wake (near wake) and four cycles of far wake. The blade airfoil wind tunnel test data is used for viscous correction on aerodynamic loads. Comparison with CFD method confirms advantages of this method.