Hydrogen reduction in molten alkali halide is an important process for the development of thermally regenerative fuel cells using hydrogen and lithium. Hydrogen reduction in LiCl-KCI eutectic melt was studied by the potential-sweep method with Ni, Fe, Co, and Cu electrodes. A reaction model, which considers not only a surface redox process but also the behavior of absorbed hydrogen in the electrode, is proposed. Based on this model, I-E curves are numerically calculated and fitted with experimental voltammograms. A good agreement is obtained between calculated and experimental data in the reversible region, and the validity of this model is demonstrated for Ni, Fe, and Cu electrodes. The Henry's constant for hydrogen in the melt and the diffusion constant were determined from the calculations as follows: {kappa}{sub H} = 5.68 x 10{sup {minus}12} mol/cm{sup 3} Pa, D{sub H{sub 2}} = 3.18 x 10{sup {minus}5} cm{sup 2}/s at 723 K.