To find the quantitative relation of temperature and the absorption cross-section of SO₂,the SO₂ with the concentration of 10 428.57 mg/m³ is detected at temperatures of 20 ℃,40 ℃,60 ℃,80 ℃ and 100 ℃ in the wavelength range of 295 nm to 315 nm,which is often used during the measurement of SO₂ absorption spectroscopy.Through qualitative and quantitative analysis on the experimental result,the quantitative formulas between temperature and SO₂ absorption cross-section at different wavelength are deduced.Moreover,a new approach is put forward to decrease or compensate the error induced by the temperature.