Abstract: Hydrogen is a promising energy to replace the fossil energy and plays an important role in the future energy systems. The municipal solid waste (MSW) with high hydrocarbon can be considered as a sustainable and renewable energy source. In order to perform efficient the energy recovery from MSW, a novel hydrogen production method in which CaO was adopted as a CO_2sorbent to increase H_2yield in the process of hydrogen production from an in-situ steam gasification of MSW was proposed. The effects of reaction n(Ca)/n(C) (i.e., the molar ratio between CaO and carbon element in MSW), the reaction temperature and moisture content on hydrogen yield and gas characterization were investigated. The results showed that, with the n(Ca)/n(C) ratio increasing from 0to 1.5, the hydrogen content and hydrogen yield increased from 25.89% to 45.90% in volume and from 10.86g/kg to 31.56g/kg in mass, respectively. The introduction of the steam can improve the activity of CaO carbonation reaction by promoting the hydrogen production. The quality of the gas production was reduced, when the content of moisture was higher than 39.45% in weight. Therefore, the optimal moisture content of MSW was 39.45% in weight. The thermal decomposition of MSW and tar could be enhanced at the reaction temperature higher than 750℃, which was greatly helpful for hydrogen production, but not useful for CaO carbonation reaction. The optimum operating temperature ranged from 700-750℃. The solid residues were characterized by XRD and SEM analysis. When the reaction temperature was higher than 750℃, the activity of CaO would be reduced, which is not beneficial to the adsorption of CO₂. In this process, the in-situ steam gasification of MSW with CaO addition for hydrogen-rich gas production is a promising way for the MSW resource conversion.