The dehumidification and drying system is designed to remove moisture from engineering plastic products in order to boost their quality and longevity. This plastic resin dryer is highly efficient and does not slow down the production process at all, while greatly increasing the level of product toughness. The dehumidifier can also realize central dehumidification drying. Moreover, a set of dehumidification drying system can be used for plastic dehumidification drying of multiple extruders and injection molding machine.