Research conclusions:The topographical and geological conditions along the Chengdu － Lanzhou Railway are very complex because of the active faults，high intensity earthquake，landslide，collapse，strewn at random，talus，dangerous rockfall，debris flow and goaf and they may be the control elements for the railway alignment． So the following principles should be followed in the railway alignment: The railway should pass the active fault with short distance and big angle by adopting the simple engineering，and for the area along the active fault，the railway should be built on the lower wall (passive wall) and kept away from the the fault as far as possible，and the railway should pass round the unfavorable geological area where the geological conditions are complex and centrally distributed and it is difficult to treat them． Also the railway should pass round the big goaf． The west line scheme，the Jushuichang scheme and the scheme of the long tunnel on the left of the Min River with better geological condition are chosen．