Korea is an industrial structure centered on manufacturing, especially the high-energy steel industry is the representative CO2 emission industry. In order to achieve the government s goal of reducing greenhouse gas emissions and respond to international carbon regulations, it is urgent to develop CO2 reduction technology. The by-product gas produced by the steel plant is refined to a certain level and used as a fuel source for the power plant or furnace of the steel plant. However, in order to provide a raw material for producing hydrogen, it is necessary to develop an efficient gas purification method for removing impurities. In this study, a CO2 removal experiment using an adsorbent in the hydrogen production process of a steel plant by-product gas was performed to examine the hydrogen production characteristics.