The demand for alternative energy is increasing rapidly because of global warming and the depletion of fossil fuels. Gasification is a technology that produces gaseous fuels through the incomplete combustion of waste or biomass. The introduction of a catalyst during gasification may increase the production of H₂ and reduce tar formation. In this study, the catalytic gasification of rice hulls was carried out using a fluidized gasifier. To improve the gas yield and reduce tar, municipal solid waste incineration bottom ash (IBA) having nanoporosity was introduced as a substitute for the fluidized bed material. Gasification was carried out at 800 °C, and the flow materials were silica sand, dolomite, and incineration bottom ash. The equivalence ratio, which is the ratio of oxygen supplied to oxygen required for complete combustion, was set to 0.3. The application of alternate fluidized bed materials (dolomite and incineration bottom ash) was effective in improving the hydrogen yield and tar reduction. This was attributed to the high Ca and Mg contents in dolomite and incineration bottom ash. Therefore, it is expected that IBA can be utilized as a catalytic fluidized bed material to replace silica sand.