An integrated hydrodynamic mathematical model is established from experimental results and a more rigorous definition is proposed for the uniformity of the axial gas distribution in a radial flow moving-bed reactor (RFMBR). A new iteration strategy is provided for the solution of the model. Simulations show the influence of the flow structure, the reactor dimension, the design of the axial gas distributor and the operation conditions on the axial uniformity of the gas distribution. This work provides a theoretical basis and useful method for the optimum design and operation of RFMBRs.