Abstract: With an extension of the railway network to the west China, the number of high-altitude railway tunnels has increased significantly. In condition of tunnel fire, the smoke diffusion will speed up and the evacuation capacity will decrease because of the low atmospheric pressure, low temperature, low oxygen content and harsh natural environment condition in high altitude area, endangering the life safety of trapped people. The classification standards for the railway tunnel group are given based on field research, theoretical analysis, numerical simulation and so on,they are defined as the adjacent railway tunnel group if the tunnel portal spacing is less than 250 m, and they are defined as the continuous railway tunnel group if the tunnel spacing is between 250- 400 m. The law of evacuation capacities in high altitude area is understood, and it is found the evacuation capacity decreases by 11.28% for every 1 000 m increase in altitude compared with that of plain area; a comprehensive reduction factor of evacuation capaci? ty, which considers the slope and altitude, is obtained. It is recommended the lengths of isolation areas of rescue emergency station in uphill and downhill directions should be no less than 700 m and 200 m respectively considering the altitude, slope and other factors. In light of the smoke diffusion law and personnel evacuation capacity, the suggestions concerning the designs of civil structures of disaster prevention and rescue like emergency rescue station both inside and outside of tunnel, emergency exit and refuge are proposed, and the rescue mode suitable for the railway tunnel in high altitude area is presented.