The growing interest in hydrogen as an alternative fuel for advanced aviation engines highlights the need for simplified combustion mechanisms suitable for modeling complex hydrodynamic, flame propagation, and detonation processes. A thermodynamic analysis method, accounting for both thermodynamic and kinetic factors, was applied to identify the most significant reactions in the detailed hydrogen combustion scheme (68 reactions). This analysis highlighted eight key reactions, for which rate constants were refined by matching the calculated combustion kinetics of a stoichiometric H₂ + O₂ mixture to experimental data. The resulting reduced mechanism M-I (12 reversible reactions) shows only minor deviation from the experimental ignition limits. Further exclusion of the two least contributing reactions (mechanism M-II) leads to significant errors in the upper ignition limit at pressures above 10 mmHg. The proposed thermodynamic approach enables effective reduction of the hydrogen combustion mechanism while maintaining sufficient accuracy for applied modeling tasks.