Abstract: A 600 MW in-situ coal gasification chemical looping combustion (iG-CLC) power generation system using Fe₂O₃/FeO as oxygen carrier was constructed by Aspen Plus software. Based on the simulation results of the system, the energy, exergy and exergy cost were analyzed respectively. Results show that the net thermal efficiency of iG-CLC power generation system is 35.38%. The component with the maximum internal exergy loss in the system is the air reactor, which accounts for 28.39% of the total exergy loss of iG-CLC subsystem components. Total internal exergy loss of the water vapor system is relatively small in the entire system, and is only 14% of the chemical looping combustion subsystem. The maximum unit exergy cost is 3.88 for air preheater in the iG-CLC power generation system, while the unit exergy costs of reheater, economizer and superheater are also larger.