Abstract:To fully understand the regional engineering geological environment and find out main engineering problems along Ya’an-Linzhi section of the Sichuan-Tibet Railway, the findings were obtained by various stages of survey and design, scientific research, aiming to provide a scientific basis for construction and operation. Geological environment and its related engineering problems were systematically analyzed. Principles of railway disaster reduction and route selection were proposed. Major engineering geological problems and research emphases were presented, which great attention should be given to during the construction and operation. The results suggested that: 1) Ya’an-Linzhi section of the Sichuan-Tibet Railway has six major engineering environmental characteristics and challenges, such as significant elevation difference, strong plate activity, frequent mountain disasters, sensitive ecological environment, harsh climatic conditions and weak infrastructure. There are five difficult problems in the construction of the project, such as extremely bad construction environment, unprecedented long and steep slope of the railway, most concentrated super-long and deep buried tunnel, arduous task of mountain disaster prevention and heavy responsibility of ecological environment protection. There are five kinds of risks, which are difficult to acquire geographic data quickly and accurately, difficult to identify and evaluate geological disasters early, difficult to guarantee super engineering and logistics, difficult to protect ecological environment, and difficult to construct major engineering and high to prevent and control risks. 2) The study area is the concentration and prone area of large-scale landslide, glacier debris flow, ice lake outburst and other mountain disasters, and all kinds of disasters are likely to form chain disasters under complex environmental conditions. The major adverse geological evolution of deep-buried tunnels under the coupling of active faults, high intensity earthquake, high geostress, high geotemperature, high pressure water inrush, will have great influence and restriction on railway engineering route selection and engineering construction. 3) Main engineering geological problems in the study area were identified by utilizing the comprehensive survey method of “Space-Air-Ground”. By adopting tunnel-crossing method to avoid large-scale and complicated shallow geological disasters, adopting targeted engineering measures such as reducing buried depth, shortening length, leaning against mountains and rivers, walking along relatively low-temperature corridors, and avoiding long and large horizontal run-off areas, it can effectively solve the bad geological problems of shallow and deep-buried tunnels. 4) Results of this study can guide the construction and operation of the Sichuan-Tibet Railway, and provide references for the survey, design and construction of the Yunnan-Tibet railway and China-Nepal railway.