The tail gas produced by synthesis of 2,3-pyridinedicarboxylic acid contains chlorine.Chlorine must be completely removed before the exhaust gas discharge to reach standard.Sodium sulfate solution and sodium hydroxide solution were used as tail gas absorption solution for controlled experiment.And the factors influencing the absorption effect of tail gas were investigated.The experimental results showed that sodium sulfate had a better absorption effect of chlorine than sodium hydroxide.And appropriate reducing the flow rate and increasing the concentration of absorption solution was beneficial to the absorption of chlorine.The absorption capacity of Na₂SO₃ can be maximized by adjusting the pH of absorption solution with 30% NaOH solution.For 50 g quinoline reaction,300 g 20% Na₂SO₃ and 500 g 30% NaOH were required to absorb Cl₂ in tail gas.In the whole reaction,no harmful gas such as Cl₂ and SO₂ was detected in the tail gas,and the absorption effect was well.