Abstract: With the expansion of Chinese power grid construction, traversing complex terrains and climatic conditions poses severe challenges to the safe operation of the grid. The cumulative damage and collapse risk of transmission tower-line systems under the influence of micro-terrain wind fields have significantly increased. To reveal the dynamic response patterns of transmission lines in micro-terrain and micro-meteorological environments, this study employs fluid dynamics analysis method to establish a numerical model of the actual terrain in the region where the transmission line project is located. The characteristics of local wind fields under mountainous micro-terrain conditions are analyzed, and the distribution patterns of wind speed terrain parameters are clarified. Subsequently, a finite element model of the transmission tower-line system is developed. Incorporating wind speed terrain coefficients and wind speed fluctuation effects, a dynamic response analysis of the transmission tower-line system under local wind field conditions in micro-terrain is conducted. The results indicate that saddle-ridge composite terrains generate significant wind speed acceleration through the narrow pipe effect and ridge effect under the dominant wind direction, while wind speed attenuation occurs on the inner side of valleys due to terrain uplift. All terrains exhibit the common characteristic of "windward acceleration-leeward attenuation." Additionally, stress concentration areas are identified at the connections of the transmission tower legs and the intersections between crossarms and the tower body. Regions with larger wind speed terrain parameters lead to significant increases in tower top displacement, main member stress, and inter-story displacement angles of the transmission line, emphasizing the necessity of considering mountainous micro-terrain environments in the wind-resistant design of transmission lines.