Abstract: In order to improve the long-distance pipeline system, the construction units will be inevitably faced with more difficult construction, and the construction of long-distance pipelines in mountain areas will become normal. Therefore, the excavation of pipeline trench in the mountain areas is the important and difficult point during the construction of longdistance pipeline in the mountain areas. In this paper, the pipeline engineering of eastern section 5 in the Third West-toEast Gas Pipeline was taken as the example. The geological and geomorphological situations along the pipeline trench were analyzed thoroughly. Then, based on the key points and difficult points of excavation technology for pipeline trench in mountain areas, the ideas that different pipeline trench excavation technologies shall be adopted according to different geological conditions were analyzed and discussed. Finally, the suggestions to increase the pipeline trench excavation efficiency and improve the pipeline trench shaping effect were put forward.