Abstract: With the simulated solar reaction system irradiated by Xenon lamp, an experiment of hydrogen making from steam-carbon reaction catalyzed by K₂CO₃ was carried out at about 700 ℃. It is found that the rate of hydrogen production with catalysts is 10 times more than that without catalysts, and there is no obvious difference in the rate of hydrogen production with the catalyst content from 10% to 20%. The oxygen-transfer mechanism for hydrogen making from steam-carbon reaction catalyzed by K₂CO₃ was discussed in detail, which was used to explain the unbalanced phenomenon of hydrogen and oxygen in reaction product. The efficiency of light energy conversion to chemical energy reaches to 13.12% in the experiment, which is better than that of photovoltaic method(10.85%). Some approaches for improving the energy conversion efficiency were proposed.