Abstract：The production of hydrogen in a large scale with clean, CO2 free and efficient way is the fundamental of hydrogen economy. However, current hydrogen production methods can not meet these demands. As a promising massive way, nuclear hydrogen production is being extensively investigated across the world. The efficiencies of hydrogen production with nuclear energy as the primary energy supplier by various processes, including high temperature steam electrolysis(HTSE) and iodine sulfur(IS) thermochemical process, are estimated and compared with that of industrial methods, such as SMR and traditional electrolysis. Results show that the estimated hydrogen production efficiencies of IS cycle and HTST are both above 50%, which is remarkably higher than the overall conversion efficiency from heat to electricity and to hydrogen.