Aerodynamic coefficients of bundle conductor lines in windy and iced zones are the foundation to investigate the dynamic responses of transmission lines, such as galloping and wind-induced vibration. In this paper, Computational Fluid Dynamics (CFD) model for aerodynamic coefficients of bundle conductors is carried out, based on which the big dataset of aerodynamic characteristics involved five input parameters including ice type, ice thickness, wind speed, sub-conductor and wind attack angle, and three aerodynamic coefficients including the lift, drag and moment coefficients, is carried out. Then, the prediction model for aerodynamic coefficients of transmission lines is established by means of Gradient Boosting Decision Tree (GBDT) algorithm. It is obtained that the proposed prediction model for aerodynamic coefficients of bundle conductor lines is with a satisfied prediction accuracy to predict the lift, drag and moment coefficient.