The present work is concerned with the modeling of hydrodynamics in the downer reactors based on kinetic theory of particulate phase. Since the gas-solid flow in the downer is turbulent, a k(p), equation expressing the turbulent kinetic energy of particles is introduced to represent the turbulent transport of particulate phase. A function of restitution coefficient with radial positions is applied to consider the wall effect on the hydrodynamics in the downer based on physical understanding. Many experimental studies of profiles of local solids fraction and gas-solid velocities in a downer with 140 mm ID are compared with the model predictions. The results show good agreements between model predictions and experimental results.