Abstract: The change in exhaust composition (such as O₂, CO₂, SO₂ and NO) at different bed depths in sintering process was studied. The results show that with the sintering process proceeding, the quantity of combustion solid fuel increases, therefore the content of O₂ decreases and the content of CO₂ increases. As SO₂ is absorbed by the sinter bed and NO is reduced by CO in the combustion zone, the contents of SO₂ and NO increase slowly. Near the burning through point, the absorption of SO₂ by the sintering bed disappears and the decomposability of SO₂ strengthens, leading to the rapid increase of SO₂ content. With the bed depth increasing, the ratio of solid fuel declines, therefore the contents of CO₂, SO₂ and NO decrease and the content of O₂ increases. So controlling the width of the high temperature zone in deep-bed sintering can efficiently reduce gaseous pollutants (CO₂, SO₂ and NO) in sintering tail gas.