Low-temperature heat pipe is widely applied for stabilizing the permafrost foundation of Qinghai-Tibet railway. The mechanism and fundamental conditions of its application are analyzed. A field test of cooling effect of heat pipe was conducted to study the energy conditions of typical cold region and structural characteristics of heat pipe. A numerical simulation by finite element method with the actually measured boundary conditions is carried out to predict the thirty years long term cooling of heat pipe in permafrost foundation. All results show that the heat pipe lowers the soil temperature effectively at the beginning and can keep lowering the temperature continuously in a long period. Thus the conclusion can be drawn that the fundamental energy conditions of the application of low-temperature heat pipe in permafrost region would not change severely under the background of global climate warming-up, and the heat pipe will be able to keep working during all its life of thirty years, ensuring the stability of the permafrost foundation.