A 3 dimensional simulation of horizontal rotating bed for glass bead particles is done and the results were compared with the experimental data available of Qian and Pfeffer el at (2001). The glass beads particle with mean diameter of 82 ƒÝm. (group A particles) is used to carry out the simulation. The rotating speed of the RFB was set at 325 rpm (34 rad/s), which is equivalent to a centrifugal acceleration of 7 "g". The continuity, momentum and constitutive equations with the proper boundary conditions, were solve to model this system. The calculated pressure drop compared with the experimental data and it shows that simulation results over predict the pressure drop at any gas inlet velocity, but predicts the same trend as the experimental data. The reason is, in the CDF model it was assumed that the gas flow through the side-wall distributor is uniform that is based on the assumption that in the experiment the gas distributor pressure drop was high enough to assure a uniform gas flow into the bed. The pressure drop comparison showed that this assumption may not be valid when the bed is in the packed condition. In order words the gas may have by passed the solids packed bed region and entered the cylinder from the top of the distributor where the bed thickness is smaller, and the voidage is high. By increasing the gas flow rate the simulated pressure drop is comparable to the experimental results and this shows that the uniform flow assumption is valid in the fluidized state.