Abstract: The corrosion behaviors of 316L stainless steel, ND steel and Q245R steel in simulated solution of acid dew point corrosion were studied by immersion test and electrochemical test. The influences of temperature, sulfuric acid mass fraction and Cl^- mass concentration on the law and mechanism of acid dew point corrosion of the three materials were analyzed. The results show that the acid dew point corrosion resistance of the three materials was ND steel, 316L stainless steel, Q245R steel in order from largest to smallest. The corrosion rates of ND steel and Q245R steel rised firstly and then decreased with the increase of Cl^- mass concentration. The corrosion rate of 316L stainless steel was influenced by the interaction of Cl^-, SO₄^2- and dissolved oxygen.