The gypsum tumble dryer is mainly composed of hot blast stove, belt feeder, tumble dryer, belt feeder, induced draft fan, cyclone dust collector, bag filter (or wet dust collector) and operation control system. The equipment adopts the fair current (or countercurrent) drying process. The working principle as following: After entering the drying drum, the wet materials are spitting into the following working areas: First, the material guiding zone. Plaster enters this zone and contacts with high-temperature hot air to quickly evaporate moisture. The material is in a large lifting flight angle is transferred to the next working area under the splicing; Second, the copy board area, in which the gypsum is dropped and pick up by the lifting flight to form the material curtain state. At this time, the material in full contact with the hot air, and the moisture in the plaster is rapid. The evaporative stripping becomes water vapor, and the water vapor is drawn away immediately by the induced draft fan to achieve the purpose of gypsum drying; the gypsum is dried in this zone to a loose state with moisture below 5-10% (or lower), after heat exchange of the material The required moisture state is reached and the final discharge zone is entered. The third is the discharge zone. The roller does not have a copy board in this zone. The material slides in this zone to the discharge port to complete the entire drying process.