Screw pump with a single screw pump, twin screw pump and three screw pump. The working principle of the screw pump is that when the screw pump is working, the liquid is sucked into the sealed space enclosed by the screw thread and the pump shell. When the driving screw rotates, the screw pump sealing volume increases the pressure of the screw pump under the extrusion of the screw thread, And move in the axial direction. Since the screw is rotating at a constant speed, the flow of liquid out is also uniform. Screw pump features: screw pump loss, good economic performance. High pressure and uniform, uniform flow, high speed, with the original direct motivation. Screw pump can transport lubricating oil, conveying fuel, conveying a variety of oils and polymers for conveying viscous liquid.