A decarbonization method of a coke oven gas and a converter and/or blast furnace gas comprises the following steps: (S1) filtering and performing impurity removal of the coke oven gas and the converter and/or blast furnace gas, and pressurizing of an MDEA (Methyldiethanolamine) barren solution; (S2) CO2 separation; (S3) purification of the coke oven gas and the converter and/or blast furnace gas;(S4) cyclic regeneration of the MDEA barren solution. The decarbonization method of the coke oven gas and the converter and/or blast furnace gas, disclosed by the invention, has the advantages of fastadsorption rate, large absorption ability, high purification degree and the like and can be used for not only removing CO2, but also removing sulfide, so that the a wide application and development prospect is obtained; meanwhile, decarbonization of the converter and/or blast furnace gas can be creatively completed through two working procedures of pressure swing adsorption coarse decarbonizationand MDEA solution fine decarbonization, the breakthrough of decarbonization of the converter and/or blast furnace gas is realized, and important significance in promoting the technological advance and economic development of refining industry in China is obtained.