Abstract: The stable isotope method was applied in the research about SO₂ heterogeneous oxidation reaction on deliquescent aerosol surface in Minnan area. By determining the abundance of stable sulfur isotope of SO₂ in the air and of soluble sulfur in the aerosol, the stable sulfur isotope reaction equation was used to calculate the ratio of homogeneous rate and heterogeneous rate of SO₂ on deliquescent aerosol surface. The results show that the ratio of homogeneous rate and heterogeneous rate of SO₂ on deliquescent aerosol surface is 1.13 in Zhangzhou area and 0.36 in Xiamen area, and the difference is caused by different relative humidity.