<p>A thermodynamic model was established to describe the shrinkage and recovery of collagen soft tissues during thermal ablation. A three-state model of protein thermal denaturation was adopted to classify collagen molecules into native, unfolded, and denatured states. By integrating the Arrhenius equation and considering the effect of external forces, the Monte Carlo method was used to determine the state of collagen molecules, enabling dynamic simulation of the denaturation process. Collagen fibers were modeled as parallel molecular array models to calculate real-time shrinkage of collagen fibers. The model was validated by comparing with existing thermomechanical coupling shrinkage experimental data of bovine left atrial chordae tendineae, showing good agreement between model predictions and experimental results. Furthermore, the model predicted tissue shrinkage under different thermomechanical protocols and identified significant model parameters through sensitivity analysis. The model can effectively predict tissue shrinkage within the experimental temperature range and tissue recovery after ablation, providing an effective predictive tool for clinical thermal ablation therapy.</p>