An unsteady model of the combustion of a single RDF pellet, which involves heat transfer and oxygen diffusion in the RDF pellet, was developed to interpret quantitatively the devolatilization and the char combustion processes of RDF. The simulation results for weight loss and temperature profile of the RDF samples made from municipal solid wastes, wood chips and polypropylene when they were heated at 10 K/min or put into the furnace at 1, 073 K were verified to agree with the experimental data. Moreover, by analysis of the temperature distribution and the conversion rate along, the radius of the RDF pellet during the devolatilization process and the char combustion process using this model, the influence of heating rate on the combustion characteristics was clarified.