Abstract: The improvement of wind power technology and the increasing demand for electric power have made the construction scale of the wind farm become larger. However, many safety issues have also been exposed in the process of the production and operation and maintenance. Overhead transmission lines in the wind farm are exposed to nature for a long time, which is likely to cause lightning accidents of ground wire and self-supporting angle steel tower. Firstly, the three kinds of commonly used overhead transmission line lightning protection technology principle and its corresponding measures were analyzed. Through collecting on-site data, the models of wire, cable, tower, grounding and arrester were established to verify that the smaller the grounding resistance was, the better the lightning protection effect was. Finally, a scheme to reduce the grounding resistance and optimize the lightning protection design was proposed to ensure the safe operation of the transmission line project in the wind farm and the stability of the power grid.