Abstract: Under the way of dry or wet flue gas recirculation mode, the fuel gas dynamic calculation model and the flue gas composition dynamic variation calculation models for the oxy-fuel combustion circulating fluidized bed boiler with the air start-up mode were established. Based on the P-R state equation of the actual gas, the operation energy consumption calculation models for the air separation unit and the CO₂ compression and purification unit were established by using the deviation function method. On this basis, the influence factors of circulating fluidized bed boiler oxy-fuel combustion and CO₂ capture power generation unit operation energy consumption were quantitatively analyzed and calculated, and the effects of oxygen purity, oxygen concentration, excess oxygen coefficient, boiler air leakage coefficient and different flue gas recirculation modes on the generation unit operation energy consumption were obtained.