Abstract: According to the application of oxidation-absorption process in Claus units of natural gas purification plants for energy saving and emission reduction, the process of SO₂ reinjected to an extended Claus unit was simulated using VMGSim software. The effects of different SO₂ reinjection position on sulfur recovery rate and combustion furnace temperature were illustrated, and the corresponding countermeasures were proposed, which will provide reference for the application of oxidation-absorption process on extended Claus unit in natural gas purification plants.