Abstract: During the process of aero-dynamicalcomputation for wind turbine rotor, one has to solve an integral equationwith respect to the radial circulation distribution. Within itsintegrand,however, an unknown circulation is included so that itbecomes an integral-differential equation. This paper proposes a numerical method to obtain a comparativelyaccurate result for the aerodynamic computation for wind turbine rotors. Thehistory of this integral-differential equation is briefly described first.Then two numerical computational methods are given. With respect to thesingularity of the integrand, an appropriate approach is also proposed.Finally, the results from aero-dynamic computation for a wind turbine rotorby using the numerical method presented and other two methods are comparedin order to illustrate the effectiveness of the method presented, aswell as to show some problems in the method with possible improvement in future.