The desiccant wheel is divided into two fan-shaped areas by a partition made of materials with high sealing performance: one deals with the 270 degree fan-shaped area of the wet air end, and the other is the 90 degree fan-shaped area of the regenerated air end. When the wet and cold air that needs to be dehumidified enters the fan-shaped area, the water molecules in the air are absorbed by the dehumidifier inside the impeller, and the dried air is sent to the dry air outlet through the processing fan.