In steel manufacturing plants, blast furnace gas is generated from a furnace in which steel ore, coke and limestone are heated and melted. It is commonly used to produce electricity or released to the atmosphere in general; however, it can be utilized as a carbon source to produce C1 value-added chemicals. In this study, we propose two production schemes for methanol production and co-production of methanol and ammonia from blast furnace gas. Both cases were simulated using Aspen Plus V12 and economics was evaluated using Aspen Process Economic Analyzer (APEA). As a result, the methanol production case produced 99.4 wt% 232 t/day of methanol and the co-production case produced 97.7 wt%, 453.4 t/day of ammonia and 99.8 wt%, 263 t/day of methanol. The total annual cost of the methanol production case is US 121.6M$/y and US 222.1M$/y at the co-production case. The NPVs are -810.4M$ in the methanol production case and -981.3M$ in the co-production case, respectively. By sensitivity analysis, it is shown that the co-production case can be more economically feasible in the aspect of NPV when the raw material cost decreases 30%.