<p>Mechanical parameters of permafrost are essential for infrastructure design and construction in cold regions. This research first proposes a combined numerical approach based on the actual pore ice and ice lens distribution in natural permafrost and the thermo-hydro-mechanical coupled model of continuous media to characterize natural permafrost’s deformation and strength behaviors under complex temperature and stress and strain boundary conditions. The internal structural images of natural permafrost based on X-ray CT were obtained, and a series of image processing methods were employed to establish digital twins of permafrost samples. According to the governing equations for moisture migration and heat transfer, based on the modified cam clay model, a coupled thermo-hydro-mechanical model for natural permafrost was established. Triaxial creep tests of natural permafrost samples were conducted, and the test results were used to verify the proposed model, yielding high agreement (<i>R</i>² &gt; 0.95, RMSE &lt; 0.02). Further, the proposed model was used to examine the effects of temperature, unfrozen water, and stress distribution on permafrost behavior, study the strength and deformation properties of permafrost under different temperatures and confining pressures, and analyze the mechanical parameters of permafrost, such as elastic modulus, cohesion, internal friction angle, and creep rate.</p>