Abstract: The corrosion behaviors of Alloy 690 in environments of ethanolamine (ETA) water chemistry condition were investigated by means of high temperature and high pressure simulated tests and low-temperature electrochemical tests, the effect of SO42- concentration was detailedly studied. The results showed that under the ETA water chemistry condition, SO42- mainly caused general corrosion and intergranular corrosion of alloy 690, the dissolution of the matrix elements Cr and Fe was promoted while the dissolution of Ni was inhibited. The dissolution of Fe increased with the increase of the concentration of SO42- while the dissolution of Ni and Cr was almost not affected.