Because of the geology, the climate and other reasons, the lightning accident occupies a large proportion of the transmission lines trip-out in mountainous area, which seriously influences the stability of the power grid and the power supply reliability. This article investigated the statistical data of lightning trip fault for 35 kV and higher transmission lines in Chongqing Changshou mountainous area in recent years, introduced the treatment scheme of lightning accident, judged the pattern of lightning accident based on the theory and site experience, and briefly analyzed the lightning trip fault. The process of lightning protection regulation was researched to propose some new ideas for lightning protection, which was popularly used in Changshou power grid. The results can provide references for transmission lines lightning protection in lightning area and mountainous area.