Abstract: The corrosion behavior of A36 carbon steel were investigated in 50 wt.% MDEA solutions with the background of the CO2 capture process in fossil fuel-fired power plants for the carbon capture and storage (CCS) purpose. Series of experiments were conducted under regenerator conditions (120 °C) with different combinations of CO2 loading O2 and heat stable salts (HSS: formate bicine and sulfate) with the exposure time of 48 h. Corrosion behavior of carbon steel were monitored by using electrochemical measurements (OCP LPR and potentiodynamic polarization) surface analytical techniques (SEM/EDS and XRD) and weight-loss method. Under the regenerator conditions the corrosion rate of carbon steel depressed with time in MDEA/CO2 solution with different CO2 loadings due to the formation of FeCO3 layer i.e. no significant influence of CO2 loading on the corrosion rate. The presence of HSS in the MDEA/CO2 systems accelerated the corrosion process at low CO2 loading whereas no notable effect was found at high CO2 loading condition. The effect of oxygen on the corrosion rate was also evaluated. The condition and mechanism of FeCO3 layer formation were deeply discussed which are key issues to control the corrosion in this environment.Key words: CO2 capture MDEA Regenerator CO2 corrosion Heat stable salts FeCO3 layer