Abstract: Aiming at the emission problem of SO₂ from the sulfur recovery unit, it pointed out that the SO₂ in flue gas is mainly from 3 sources, including liquid sulfur degassing, hydrogen reduction & absorption tail gas, and other non common reasons. According to different sources, the countermeasures to reduce the total SO₂ emission concentration in flue gas were put forward and the Research Institute of Natural Gas Technology emission reduction technology were invented. The technology mainly includes H₂S deep removal solvent CT8-26, titanium based sulfur recovery catalyst CT6-8 and new hydrogenation reduction & absorption hydrolysis catalyst CT6-11B. The technology is applicable to the existed sulfur recovery unit with hydrogen reduction tail gas treatment, in particular which has an independent hydrogenation reduction solvent regeneration device. It can reduce the SO₂ mass concentration in tail gas exhausted from sulfur recovery unit to lower than 100 mg/m³ and provide a new solution scheme for tail gas emission to the standard of sulfur recovery device.