The effect of different parameters on SO2 absorption was investigated in a semi-batchwise bubbling stirring reactor. From the experimental results, an increase of the gas flow, which substantially decreased the residence time of the gas in liquid, led to a quick reduce of the time of 100% removal efficiency of SO2. The addition of CaCO3 increased the removal efficiency of SO2 significantly. With increasing the concentration of CaCO3, the time of SO2=100% was almost increased linearly. The increase of the stirring speed prolonged the time of SO2=100% at first, but when beyond a certain value, no further effect of the stirring speed was observed, which showed that the mass transfer of SO2 in slurry was controlled by both gas and liquid mass transfer. Citric acid displays a good buffer action on SO2 absorption. The addition of citrate prolonged the time in which the SO2 removal efficiency remained high valves.