Based on the engineering construction method，the refreezing process of backfill is investigated by model test method under simulated ambient temperature. The results indicate that the frozen layer thickness increases with the freeze-thaw cycles when the simulated average temperature is -2.71 ℃. The thawing depth is about 6.1 cm at maximum ambient temperature in every freeze-thaw cycle, and the frozen layer thickness increases to 20.0 cm after 13 freeze-thaw cycles. The pile foundation has an effect on the refreezing process of backfill in the horizontal and longitudinal directions, but its scope of influence is limited. The interface temperature between air and pile is close to the air temperature, but the interface temperature between air and soil is very different from air temperature. The air temperature is higher than air-soil interface temperature by 5.0 ℃ at the maximum ambient temperature, and lower than air-soil interface temperature by 6.7 ℃ at the minimum ambient temperature. This experiment results help to further understand the actual refreezing process of backfill, and provide reference for determining the control conditions in model test and the boundary conditions of numerical simulation.