Abstract: With the development of thermal energy and thermal power pipeline engineering and the large-scale application of ground-source heat pump technology in China, the problems of stress, deformation, seepage, and temperature coupling of rock and soil have become research hotspots in geotechnical engineering. Under a long-term loading, the deformation and strength of rock and soil bodies (especially the soft soil) change with time and are of obvious rheological characteristics. The traditional rheological models do not consider the effects of temperature and temperature rise mode on their parameters. In order to better reflect the rheological consolidation characteristics, the viscoelastic-plasticity of the soft clay is considered, the improved Nishihara model under thermo-mechanical coupling is established based on the Nishihara model by introducing the temperature expansion coefficient, and the stress-strain relationship is given. The analytical solutions are obtained for one-dimensional heat consolidation equation by using the Laplace transform and the inverse transform. The results show that when the consolidation pressure is constant, the temperature rise will accelerate the consolidation of the soil. When the temperature is constant, the pore pressure in the soil decreases with the increasing consolidation pressure. When the elastic modulus of the improved Nishihara model is increased, the speed of pore pressure dissipation and the consolidation of the saturated soil are accelerated. The thermal expansion caused by temperature of the soil particles has a very small effect on the dissipation of the pore pressure. The smaller the viscous coefficient, the faster the pore pressure dissipates and the faster the soil is consolidated. The experimental results are in good agreement with the thermal coupling of the viscoelastic-plasticity of the soil. The improved Nishihara model can better describe the thermal coupling characteristics of the soil.