Due to the influence of different climate conditions, topography and other factors, the distribution of thunder varies greatly in different regions. It is of significant practical value to study the law of thunder distribution in complex terrain. In this paper, the local terrain division of transmission line area is carried out, and the improved cluster analysis method based on DBSCAN algorithm and OPTICS algorithm are used to obtain the temporal and spatial distribution of single lightning activity in different terrain. According to the results, it is found that the temporal and spatial distribution of lightning activity is slightly different in different terrain. Among them, the lightning activity tracks along the canyon wind channel and ridge terrain are more than the lightning activity tracks along the valley and river terrain. At the same time, the lightning frequency and lightning current amplitude before and after a single lightning activity passing through different terrain are analyzed to further analyze the influence of terrain on lightning activity. The research on the distribution law of lightning on the macro terrain and local terrain near the transmission line can provide engineering reference and theoretical reference for the future differentiated lightning protection work.