China possesses diverse and intricate topography, with widespread micro-terrain regions that can influence local meteorological elements such as wind speed and temperature. One of the impacts of micro-terrain on the safe operation of transmission lines, especially for those located in mountainous areas, is conductor icing. To reveal the influence of micro-terrain on transmission line icing, this paper focuses on one of the most common micro-terrains, high mountain ridges, which is widely distributed in mountainous areas. The disturbance effects of typical alpine watershed on airflow are analyzed using computational fluid dynamics (CFD) simulations. The degree of airflow disturbance on the windward and leeward sides of a mountain ridge is different. The negative acceleration zone is located at the base of the windward side, and it gradually becomes a positive acceleration zone upward from the base of the mountain. The maximum acceleration ratio is reached at the top of the mountain. At a height of 10 m below the ground, the negative acceleration zone appears at the base of the mountain, and the degree of disturbance is proportional to the slope. The stronger the slope, the greater the negative acceleration effect, and the minimum acceleration ratio appears at 100% slope. Unlike the base of the mountain, the sensitivity of the acceleration ratio at the top of the mountain to the slope is lower.