|Low-priced hydrogen is required in petrochemical industry for producing low-sulfur oil, and upgrading low-grade crude oil since environmental regulations have been reinforced. Steel industry can produce hydrogen from by-product gases such as Blast Furnace Gas (BFG), Coke Oven Gas (COG), and Linze Donawitz Gas (LDG) with water gas shift (WGS) reaction by catalysis. In this study, we optimized conditions for WGS reaction with commercial catalysts by BFG and LDG. In particular, the influence on activity of gas-hourly-space-velocity, and H2O/CO ratios at different temperatures were investigated. As a result, 99.9%, and 97% CO conversion were showed with BFG, and LDG respectively under 350°C High Temperature Shift (HTS), 200°C Low Temperature Shift (LTS), 3.0 of H2O/CO, and 1500 h-1 of GHSV. Furthermore, 99.9% CO conversion lasted for 250 hours with BFG as feed gas.