Abstract: In this paper, specific exergy consumption was put forward to evaluate the thermo-economy for the CO₂ capture system of a power plant. Firstly, specific exergy consumption of the regeneration can directly reflect the energy consumption level of the technology and equipments of the regeneration process of CO₂ capture system. Secondly, specific exergy consumption of the extracted steam, which is a comprehensive evaluating parameter, can reasonably and comprehensively assess the degree of perfection of steam energy utilization process of the CO₂ capture system. Finally, exergy efficiency is introduced to evaluate the effective degree of the available energy utilization during the temperature reduction process of the extracted steam.