Abstract: Considering the characteristics of frost heaving and thawing of permafrost ， combining with the only supporting structure of L-type retaining wall used in the section from Golmud to Lhasa , Qinghai-Tibet Railway , the ground temperature, earth pressure and frost heaving forces and level deformation are tested. Due to the excavation and construction disturbance, the ground heat balance of the natural state is damaged. All the test indices are affected by cyclic ground temperature. But as an open project engineering structure, as long as there are no new disturbances, this balance is to gradually form a stable state, or to recover. In addition, the earth pressure and frozen-heave force should be revised by the actual deformation.