The new method of simultaneous disposal of CO2 and H2S in coal gas generated during underground coal gasification ( UCG) using industrial waste alkali liquor is put forward and studied for the first time. The rationale of absorption of CO2 and H2S by the alkali liquor is analyzed, and the mass transfer model for the above process is established. The impact of the existence of H2S on absorbing CO2 by the alkali liquor is studied on the basis of the model experiment. Research shows that as the velocity of coal gas increases, the selection coefficient of H2S improves, the temperature rises, the selection coefficient of H2S deceases, but the removal rate of CO2 increases. By means of study, it can be found that the removal rate of CO2 can reach more than 60% under the conditions of the suitable concentration of the alkali liquor and the ratio of liquid to gas, the heat value of underground coal gas can heighten by 12.3%, 17.7%, and over 20%, respectively, when the removal rate of CO2 is 58%, 80%, and greater than 90%.