The downer of circulating fluidized bed was then successfully simulated using computational fluid dynamics model with the Eulerian approach, the kinetic theory of granular flow and the best fitted modeling parameters. The computations gave a close comparison of the solid volume fraction, solid mass flux and system gauge pressure with three different experimental conditions. Finally, the obtained computational fluid dynamics model was applied to calculate the system hydrodynamic characteristics and the system turbulent properties, which are the solid volume fraction, the axial solid velocity, the radial solid velocity, the power spectrum, the normal Reynolds stresses, the turbulent kinetic energy, the granular temperature and the energy spectrum. These calculated results can be used as an explanation for the in-depth system flow structure in the downer system.