Research conclusions: From the railway alignment，the locations of the geothermic tunnels in the section between Semai － Renbu of the Lhasa － Rikaze Railway are in the plateau and mountain areas with valley． The railway alignment should be away from the places of landslide，mudflow，talus，rock falling and fault as much as possible． Especially the alignment should be away from the geothermic development area． The track should cross the geothermic zone with big angle and passes through the zone by the shortest distance． A safe，reliable，reasonable and economic alignment is determined．