Abstract: It is of key importance to understand and master the law of gas-solid two-phase flow and reaction mechanism in UO₂ hydrofluorination second stage fluidized-bed for its engineering application. The traditional experimental method has high cost and long periodic, so the numerical simulation method has become the choice of more researchers and designers. Based on the CPFD method, the mathematical model of the UO₂ hydrofluorination fluidized-bed was established, the drag model applicable to the UO₂-UF₄ system was screened out, and the Arrhenius equation for the hydrofluorination reaction was deduced. According to the model, researches on the influence of the HF inlet, the operating gas velocity, and the solid diameter on fluidization were conducted. The simulation results show that the current design parameters are reasonable, and UO₂ hydrofluorination second stage fluidized-bed can form a good temperature gradient distribution and the percent conversion is close to the production requirement. The mathematical model of UO₂ hydrofluorination fluidized-bed based on CPFD can accurately simulate the operation of fluidized-bed and provide useful references for enlarged design and operation.