<p>Understanding the evolution of diffusive hydrogen during mechanical loading is essential for clarifying its role in hydrogen-assisted damage. In this study, a one-way coupled diffusion analysis framework is adopted to model hydrogen desorption during the in situ thermal desorption spectroscopy (TDS)-tensile process. The mechanical response is first established experimentally, and the corresponding stress and strain conditions are treated as fixed inputs to the diffusion problem. The mathematical formulation integrates the theoretical foundations of Sofronis and McMeeking with the McNabb–Foster equation and is numerically implemented using a hybrid Euler scheme. Key characteristics, including lattice hydrogen concentration, trap occupancy distribution, and hydrogen flux evolution, are evaluated. The effects of applied tensile stress, trap type and density, initial occupancy levels, and activation energies are systematically examined. The results reveal that a moderate detrapping energy provides the most effective trapping performance, and the critical threshold at which traps lose their effectiveness is quantified. Furthermore, a fitting procedure is developed that produces physically reasonable parameters while significantly reducing computational cost. This methodology was implemented in the experiment, which enables the determination of optimized trapping and detrapping kinetics from predefined initial conditions and boundary constraints, offering a robust tool for elucidating hydrogen–microstructure interactions.</p>