The desufurization in dilute sulfuric acid solution, acidic ferric solution, and microbial solution (Thiobacillus ferrooxidans) was studied in this paper. The concentration of ferric, pH value and time all affect the rate of desulfurization. The experimental results showed that in dilute sulfuric acid solution the absorption of SO2 was a physical absorption. In acidic ferric solution, the ion of ferric can not only catalyze but also oxidize SO2. The effects of desulfurization became obvious along with high concentration of ferric and pH value. Desulfurization rate was up to 90% when pH value was 2.0 and the concentration of ferric was 1.5 g/L. In microbial solution, the effects were also influenced by the concentration of ferric and pH value. Thiobacillus ferrooxidans had an ability of oxiding the ion of ferrous and S(IV). The results of desulfurization was the best at the concentration of ferric 1.5 g/L and pH 2.0.