Abstract: The computational fluid dynamics-discrete element-immersed boundary method (CFD-DEM-IBM method) is extended to simulate the decomposition of ozone in a cylindrical bubbling fluidized bed, where the effect of complex geometries on the fluid flow is imposed by immersed boundary method. The expanded bed height and the global circulation patterns obtained from CFD-DEM-IBM simulations are in a good agreement with the results reported in literatures. The effects of inlet gas velocity and static bed height on the ozone conversion are also investigated, and the simulation results are consistent with the experimental data of Fryer and Potter (Fryer and Potter, 1976 [1]). Present study proved the feasibility of simulation of catalytic reaction processes in fluidized beds with complex geometries using CFD-DEM-IBM method.