Abstract: In order to lower the surface EFI of the sub-conductor and reduce the corridor width of overhead transmission lines, a simulation study is conducted. Firstly, a model is established with FEM to calculate the EFI on and around the surface of overhead transmission lines. Secondly, the FEM is used to calculate the average EFI on the surface of the maximum phase conductor under unsymmetrical configuration, the maximum EFI at the level of one meter to the ground under the line, and the corridor width. Finally, it is found though a comparative data analysis that the horizontal elliptical configuration of sub-conductors is superior to the circular configuration. The simulation results show that the horizontal elliptical configuration of eight-bundle conductors with inverted triangular layout can reduce the average EFI on the surfaces of the maximum phase conductor, the maximum EFI at the level of one meter to the ground under the line, and the corridor width. When used in overhead transmission lines, this configuration can reduce the corona loss and the level of radio interference and audible noise as well as the tower height.