Abstract: The dimensional effect of temperature field in permafrost embankment was a general term for size effect of embankment and structural effect of pavement.Based on the equivalent parameter model of heat-transfer considering phase change of ice and water and moisture transfer,the size effect of embankment with different heights,widths and side slope angles and the structural effect of asphalt pavement,cement concrete pavement and gravel pavement were simulated to analyze variation of embankment temperature field in permafrost regions on the plateau.It was shown that the permafrost was sensitive to dimensional effect of the highway on the Qinghai-Tibet Plateau and the variation of temperature field of embankment was directly influenced by the embankment size.The heat absorption of frozen foundation was negatively dependent on embankment height and side slope,but positively dependent on the embankment width.The influence of heat absorption of asphat parement on the temperature field was about 1.7 times that of gravel parement.According to the research,it could be concluded that the wide embankment and thermal effect of asphalt pavement were the two key factors for the variation of temperature field of frozen soil embankmentcompared with other projects.Therefore,it was necessary to emphasize the engineering stabilization and security problems from the dimensional effect of highway on permafrost foundation in expressway construction on Qinghai-Tibet Plateau in the future.