A comprehensive one-dimensional model was developed in this work for the simulation of a riser regenerator. The model incorporates the hydrodynamic characteristics of fluidized bed risers and the detailed reaction kinetics of FCC (fluid catalytic cracking) catalyst regeneration and can be used to predict the axial profiles of temperature, oxygen concentration and coke content of the catalyst in the riser. The validity of the present model was confirmed by the experimental data from a pilot demonstration unit. Based on the simulation, effects of solids flow patterns and other parameters including gas velocity, spent and regenerated solids fluxes, temperatures of air and spent catalysts as well as carbon content on the spent catalysts have been systematically examined. The simulation results have provided the necessary information for the optimal design and operation of a FCC riser regenerator unit, presently in operation in China.