A device for screw pressing and dewatering Enteromorpha, comprising a screw dehydration assembly, a press dehydration assembly, an overrunning clutch, and a fixed frame, characterized in that the screw dehydration assembly includes a feed inlet, a screw protective cover, a screw blade shaft, and a bearing. The upper end of the spiral protective cover is provided with a feed inlet, and the two ends of the screw blade shaft are fixed on the spiral protective cover through bearings; the press dehydration assembly includes a press protective cover, a press plate, a press shaft, a discharge port, a motor, a drain pipe, Bearings, a motor is installed at the rear end of the press guard, a discharge port and a drain pipe are arranged at the lower end of the press guard, and a press structure composed of a press shaft and a press plate is arranged inside the press guard; An overrunning clutch is arranged between the forming and the press dehydration assembly; a fixed frame is arranged at the lower end of the screw dehydration assembly and the press dehydration assembly. The device can effectively realize the dehydration treatment of enteromorpha, and has good dehydration effect and high working efficiency.