Abstract: Using perovskite as oxygen carrier and wood chips as fuel, the thermodynamic analysis of 10 MW_th biomass chemical looping combustion system is conducted. The results obtain the reactor size and key thermal balance parameters required by the system under self-thermal operation conditions. The results are as follows: The results are as follows: the air reactor is efficient rapid fluidized bed design, its bed height is 45.5 m, cross-sectional area is 2.96 m², apparent air velocity is 4.37 m/s; the fuel reactor is designed as two upper and lower layers, the upper layer is fast fluidized bed and the lower layer is bubble fluidized bed. The total height of the bed is 31.06 m, the height of the upper bed is 26.21 m, the height of the lower bed is 9.31 m, the cross section area of the upper and lower layers is 1.94 m² and 7.76 m² respectively, the apparent gas velocity of the upper and lower layers is 3.52 m/s and 0.31 m/s respectively, and the circulation rate of the oxygen carrier is 101.14 kg/s under the heat load condition. The thermal calculation results provide a reference for the design of a chemical looping combustion system with biomass as a fuel