Combustion and emission characteristic of fluidized beds are mainly determined by bed hydrodynamics. Fluidized bed hydrodynamics is a mechanism that explains gas-solid two phase flow and their interactions in fluidized beds. In this study, gas-solid two phase flow hydrodynamics in a cold model fluidized bed was numerically investigated by using PHOENICS computational fluids dynamics (CFD) code. In the model, the effects of particle density, superficial velocity and particle diameter on flow hydrodynamics were investigated. In the simulations, air was used as a gas phase, and spherical glass bead was taken as solid phase. It has been determined that solid circulation rate was influenced by the changes in particle density, superficial gas velocity and particle diameter.