Abstract: Fumigation and ambient exposing experiments were conducted to evaluate the feasibility of using SOD activity in the leaves of broadbean (Vicia faba) as bioindicators of SO2 pollution. Fumigation experiments were conducted in dynamic fumigation systems with SO2 concentrations of 0.1312 and 0.2601mg·m-3, respectively. The SO2 fumigated leaves had higher SOD activities than the control, and higher concentration (0.2601 mg·m-3) of SO2 caused greater increase in SOD activity than lower concentration (0.1312mg· m-3). The SOD activity in SO2 fumigated leaves increased gradually at the beginning and reached a relatively stable stage after several days of treatment. Ambient exposing experiments were conducted with the form of plant- meter in 8 sites for 21 days. The SOD activity correlated significantly with the rate of sulfatization (RS) in the air at the level of p<0.01. The degrees of SO2 pollution at sample sites were evaluated with SOD activity and RS respectively. RSs were also estimated by SOD activity, and then compared with the actually detected values. The 95% confidence interval was also made. All of our results suggest that it is feasible to use SOD activity in the broadbean leaves as bioindicators for SO2 pollution.