Abstract: Oxy-fuel combustion technology in circulating fluidized beds (CFB) offers advantages such as broad fuel adaptability, strong pollutant control capability, and low carbon capture cost. First, the development and application of key sub-models, including gas-solid two-phase flow, radiative heat transfer, combustion reaction, and pollutant conversion are reviewed. Then, the progress of numerical simulations is summarized, covering studies from laboratory-scale to industrial full-scale CFB oxy-fuel combustion boilers. The results indicate that the Euler-Lagrange computational framework has become the primary simulation approach, and relevant particle-cluster models can accurately characterize particle motion characteristics in the furnace at low computational cost. Under oxy-fuel conditions, the high concentrations of CO₂ and H₂O alter the flue gas thermophysical properties and radiative characteristics, necessitating the use of modified radiation models. The simulation of char combustion must fully account for the CO₂ gasification reaction. Pollutant simulations commonly adopt global reaction mechanisms. Measurements and simulations of large-capacity units have confirmed their superior overall performance. However, current research still faces challenges such as insufficient adaptation of dedicated sub-models and difficulties in industrial-scale simulations. Future efforts should focus on developing dedicated sub-models tailored to oxy-fuel conditions and deepening full-process simulations in conjunction with engineering applications.