Mesoporous alumina (MA) with a higher ability to simultaneously remove SO₂ and NO was prepared by the evaporation-induced self-assembly process. The adsorption capacities of MA are 1.79 and 0.702 mmol/g for SO₂ and NO, respectively. The Brunauer–Emmett–Teller method was used to characterize the adsorbent. Simultaneous adsorption of SO₂ and NO from flue gas over MA in different operating conditions had been studied in a fixed bed reactor. The effects of temperature, oxygen concentration and water vapour were investigated. The experimental results showed that the optimum temperature for MA to simultaneously remove SO₂ and NO was 90°C. The simultaneous adsorption capacities of SO₂ and NO could be enhanced by increasing O₂ when its concentration was below 5%. The changes of simultaneous adsorption capacities were not obvious when O₂ concentration was above 5%. The increase in relative humidity results in an increase after dropping of SO₂ adsorption capacity, whereas the adsorption capacity of NO showed an opposite trend. The results suggest that MA is a great adsorbent for simultaneous removal of SO₂ and NO from flue gas.