Compared with the traditional methods of removal SO2 from flue gas, the organic solvent absorption has some advantages as low investment, high SO2 absorption efficiency and desorption efficiency. For the industrial application of organic solvent absorption as soon as possible, some laboratory research on selectively removing SO2 and NOx from flue gas in the presence of CO2 and an enlarged experiment has been done with a novel absorbent of Mn(II)+ DMSO. The effect on desulfurization selectivity for absorbents is studied. And the regeneration capacities for absorbent are researched. The result shows that the novel absorbent has not only strong desulfurization efficiency, but also good selectivity for SO2 and CO2, the feasibility of desulfurization absorbent has been proved.