The dehydration process of the screw press dehydrator is divided into two stages. In the first stage, the screw auger is used for dehydration. The screw auger is divided into three sections: the transmission section, the compression section and the discharge section. The transmission section ensures that the material enters the equipment smoothly. The stage becomes smaller, due to the gradual reduction of the transmission space, the pressure is gradually increased on the material, forcing the volume of the material to shrink to squeeze out the water; the second stage uses the material blocking device to dehydrate, when the material enters the spiral auger discharge section, the spiral The auger will apply axial thrust to the material to push it out of the discharge port, and at the same time, the material blocking device pressurized by the air pressure device will exert a reverse force on the material to be pushed out, thereby forming a squeezing force for two-stage dehydration of the material.