The process of bubbles from formation to eruption was simulated by using the two-fluid model combined with the particle kinetic theory to investigate the flow characterization of gas-solid in a bubbling fluidized bed. The velocity distributions of solid-phase in different axial height were also studied. The results show that the numerical simulation method can success simulates the flow characterization of gas-solid bubbling fluidized bed. The flow characterization in bubbling fluidized bed is circulating flow structure, while the central region is upward flow and the wall region is downward flow. The simulation results agree with the experiment results.