Abstract: The windage yaw of a 500kV ultra-high voltage (UHV) overhead transmission line under the action of stochastic wind load is numerically investigated. A multi-body model consisting of bundle conductors, suspension insulator strings, clamp and spacers of a typical 500 kV line section is set up based on the characteristics of the structure and the motion of the overhead transmission line. Fluctuating wind speeds based on Kaimal spectrum, which reflects the change of wind speed with height above ground, and the Davenport coherence function, are numerically simulated by means of WAWS. Based upon the statistic results of the windage yaw of the suspension insulator string, obtained by the transient response analysis of the numerical model, the shortcoming of the calculation method of the windage yaw in the current design code is discussed, and it is concluded that a dynamic load factor should be introduced in the calculation of wind load acting on the conductors and insulators to accurately determine the windage yaw of the suspension insulator string.