Abstract: Based on a new mechanismic model proposed by the authors recently which accounts for the heat transfer modes of conduction, convection and radiation in fluidized beds, a quantitative analysis of characteristic regions of heat transfer is presented in this paper. A new scheme of heat transfer regions is shown with the Archimedes number representing the fluidizing property of particles and Planck number reflecting the relative importance of conduction and radiation. Nine characteristic regions are defined,according to the change of dominant heat transfer modes, which are useful in the optimum design and normal operation of fluidized bed equipment.