Abstract: Thermodynamic analysis of Performance of steam methane reforming hydrogen production system connected with high temperature gas cooled reactor is presented, which provides a framework for further detailed research. Complete reaction model and equilibrium reaction model have been developed. System efficiency and hydrogen output variation related to process parameters is researched. Limit value of performance index and optimum process parameter are determined. Comparisons of equilibrium reaction model prediction to experimental data showed equilibrium reaction model is appropriate for preliminarily analyzing the system.