The EulerianEulerian model with kinetic theory of granular flow was applied to evaluate the gassolid flow behavior in a large-scale polydisperse fluidized system for polysilicon chemical vapor deposition growth. The uniform particle system was well validated on the basis of the empirical correlations and experimental data after parametric analysis on drag force, particleparticle collision, and wall boundary condition, and furthermore the fluidization quality in the polydisperse system by the validated computational fluid dynamics model was basically the same as that in the uniform one. The results showed that the energy minimization multiscale-based drag model had remarkable advantages in the prediction of the core-annular flow structure and mesoscale flow characteristics in a large-diameter fluidized bed, as compared to the Gidaspow model. Moreover, effects of particle aggregation and the fluidization ratio on solid distribution in the polydisperse system were also investigated, revealing an accumulation of small particles at the near-wall and upper regions and an increase of bubbles at high fluidization ratio, respectively.