Cooling effect of the two-phase closed thermosyphon (heat pipe) is always represented by ground temperature decreasing in embankment , lifting up of permaf rost table , and freezing period elongating. Effective radius of the thermosyphon and “generated cold amount " in cold seasons are the main index for further quantifying the effect . Unfortunately , owing to no thermal probe binding down the external wall of the thermosyphon , it is of great difficulty in getting quantified effect in Beiluhe thermosyphon embankment . In this article , using the geological bore data and ground temperat re data of the Qinghai-Tibet Railway , the heat budget with temperature variations , heat from near-surface layer , heat from deeper layer and heat budget for phase transition , which are induced by permafrost table variations , are calculated , and finally the ambient heat budget is also calculated out . Comparing the ambient heat budgets between the right-shoulder borehole in a thermosyphon embankment and in a traditional embankment , it is found that the thermosyphon embankment keeps releasing heat while the others keep absorbing heat . Afterwards , a same comparison between the left-shoulder borehole (south slope) and the right-shoulder borehole (north slope ) shows that the horizontal heat budget of the former is about 3/4 of the latter . Because of the south/north slope difference , air temperature in the north slope is lower than that in t he south slope. With operation of the thermosyphon , the ground temperature of the north slope decreases much more than that of the south slope. Applying the insulation board to maintain the cooling effect makes the ground temperature at 1.0 m ( below insulation board) in the right-shoulder borehole lower than that in the left-shoulder borehole , while the ground temperatures at 0.5 m (above insulation board) are almost the same in warm seasons. So the difference of ground temperature between 0.5 m and 1.0 m in the north slope is larger . At last , based on the ambient heat budget of the right-shoulder borehole , the whole heat budget of the embankment is estimated , and an average “generated cold amount " of a single two-phase closed thermosyphon is estimated to be 1 259 MJ per year . Considering the cooling effect in the right-shoulder borehole is more than to the average , the true value is less than the calculated one.