Fluidization conditions in a circulating-fluidized bed (CFB) can vary dramatically, from bubbling to circulating regimes. The granular Eurlerian models have been used to simulate the bubbling and slugging behavior of gas and solids in CFB. Considering the dielectric properties and rapid movement of solids in CFB, electrical capacitance tomography (ECT) is particularly suitable for measuring the concentration and distribution of solids in CFB to verify the simulation results. The simulation results by computational fluid dynamics (CFD) analysis and experimental results obtained by ECT are reported, and compares the simulation and experimental results first time, including the solids concentration profile, temporal variation of average-solids concentration, autocorrelation coefficient and frequency spectrum. (c) 2006 American Institute of Chemical Engineers.