An unsteady mathematical model of superheated steam fluidized bed drying process is established based on the transport process principles and computational fluid dynamics (CFD) method. The vapor-solid two-phase turbulent flow in the drying chamber is described with the Eulerian-Eulerian multiphase model. The model is solved by computer numerical simulation. The drying experiments of wet rapeseeds are conducted in a normal atmosphere. The experimental results agreeing well with the simulation results show that the mathematical model of drying process is effective.