Abstract:To reveal the frozen soil subgrade deformation and the destruction rule which caused by the three-way coupling model, the temperature field of seasonal frozen soil subgrade, the stress field and the summer rain and the ice crystal melting producing seepage. According to the coupling theory of thermo- hydro-mechanical, proposing mathematics mechanical model which coupled by temperature field, deformation field and seepage of taking phase changing into consideration, the model manifests the coupling mechanism of solid skeleton, the ice and the water. In simulation analysis, compared only receiving temperature load with the temperature load and the vehicles load, gets deformation and destruction rule of frozen soil subgrade, and the findings has certain guiding sense to the frozen soil subgrade construction and the maintenance.