To reduce the emissions of sulfur dioxide (SO₂), a desulfurization method which was based on liquefaction and separation of SO₂ by chilling the flue gas was put forward. The cryogenic desulfurization process was designed based on Aspen plus. The steady state process was simulated using SRK (Soave-Redich-Kwong) method, and the effects of temperature, pressure and concentration of SO₂ on the separation efficiency of cryogenic desulfurization were analyzed. A cryogenic desulfurization test bench was built and the verification experiments were carried out. It was found that when the mass concentration of SO₂ was 1 000 mg/m³, SO₂ removal efficiency increased from 40.2% to 73.2% when the temperature of fuel gas decreased from -15 ℃ to -45 ℃ at 500 kPa; the removal efficiency can be improved by increasing SO₂ concentration. The comprehensive results show that cryogenic desulfurization system has good liquefaction and separation efficiency. To keep the SO₂ removal efficiency above 80%, the process parameter range for the system should be under -35 ℃ and above 2 000 kPa.