The hydrogen storage bed is a crucial component of the storage and delivery system used in tritium plants for fusion reactors. Zr0.8Ti0.2Co alloy is used as the primary hydrogen isotope storage material in the bed. To reduce the impact of methane generation on the activated bed performance, this study tested the decarbonization performance of hydrogen storage beds using chromatography and mass spectrometry. Decarbonization tests were conducted on Zr0.8Ti0.2Co alloy, hydrogen storage beds, and vacant hydrogen storage beds. Research indicates that the hydrogen storage bed decarbonization process can be divided into two main stages. Stage 1 involves the preferential reaction of carbon oxides adsorbed on the surface layer of the stainless steel vessel material and Zr0.8Ti0.2Co alloy with hydrogen at high temperatures, resulting in the synthesis of methane. In Stage 2, methane is generated by cementite (Fe3C) in stainless steel with hydrogen under the catalytic effect of the Zr0.8Ti0.2Co alloy, which is less than that in Stage 1. This study on the decarbonization of hydrogen storage beds reveals the mechanism of methane generation. This information can guide the selection of materials used in the Zr0.8Ti0.2Co hydride bed and the decarbonization process before application.