Given that high CO2 levels in the atmosphere cause important environmental problems, such as greenhouse phenomena, which have consequences such as global warming and ecosystem change. Due to this, the emergence of new and economical methods for separating this gas is essential. Trapping and absorbing CO2 by monoethanolamine in the absorption tower is the most common CO2 capture method. In this study, the effect of different operating conditions such as the solvent flow rate (0.75, 1 and 25.1 lit/min), the solvent temperature (35, 45 and 55 °C), the inlet gas flow rate (50, 75 and 100 lit/min), the concentration of monoethanolamine (2.5, 3.5 and 5 kmol/m3), reboiler heat load (1.4, 1.8 and 2.2 kW) and the CO2 concentration of flue gas (5, 10 and 15%) on CO2 absorption investigated. For this purpose, absorption percent and mass flux considered as the responses. The results showed that the highest percentage of CO2 absorption achieved at operating temperature of 45 °C, solvent flow rate of1.25 lit/min, gas flow rate of 50 lit/min, thermal charge of 2200 kW, MEA concentration of 5 kmol/m3, and concentration of 5% CO2 in the flue gas.