The control equations that describe the drying process of porous materials are given. Firstly the present research status of centrifugal fluid bed (CFB) is introduced. Then by using and revising the methods which are used to deal with the processes of drying in common fluid bed, and considering some particular limits and characters in CFB, the mathematical expressions for inner procedure of CFB are also developed. On the basis of the results gained the paper the math simulation of drying process in CFB can proceed smoothly.