A novel absorbent sodium lactate (NaLa) aqueous solution (aq) for SO2 absorption is reported. SO, in simulated flue gas is reversibly absorbed in NaLa aq. The absorption capacity of SO, in the absorbent increases with increasing NaLa content and SO2 concentration, and decreasing temperature. Compared with the absorbents reported in the literature, the absorption capacity of SO2 in NaLa aq. is much high, for example, 50 wt % NaLa aqueous solution can absorb 0.130 g SO2/g absorbent at a SO, concentration of 2.5 vol % and 40 degrees C. Importantly, NaLa (aq) exhibits high reversibility and long-term stability, indicating a promise for the desulfurization of flue gas. The absorption mechanism is proposed to be the replacement of lactic acid (HLa) by sulfurous acid (H2SO3), which is dissolving SO, in water. generated by dissolving SO2 in water.