Abstract: Under the increasingly stringent environmental protection situation, it is particularly important to control SO₂ emission during the shutdown of sulfur recovery unit in natural gas purification plant. Based on the analysis of the sulfur removal process during shutdown, the factors such as the degree of sulfur removal, the time of sulfur removal and the amount of SO₂ emission during sulfur removal were analyzed and discussed. For the common sulfur recovery process units, the optimization scheme of sulfur removal during shutdown was put forward. The results showed that the mass concentration of SO₂ emission could be significantly reduced when the super Claus reactor was put into the final stage; the conventional Claus unit with Scot tail gas treatment unit could improve the sulfur recovery rate and reduce SO₂ emission when the tail gas treatment unit was put into operation in a safe and controllable state. Low temperature Claus process could significantly reduce the SO₂ emission rate by optimizing the switching frequency and other operations, and achieve high efficiency and low emission sulfur removal effect. The above discussion and practice could provide reference and suggestions for the production operation optimization and application.