The utility model is composed of a pair of gears which are arranged in a shell. The gear shell is provided with an end cover shell on both sides of the gear, and each of the interdental grooves of the end cover and the gear forms a plurality of sealed working chambers. When the gear rotates in the direction of the figure, the right oil sucking chamber gradually disengages due to intermeshing gear teeth, and the working volume of the sealing gradually increases to form a partial vacuum. Therefore, the oil in the oil tank is sucked by the oil under the action of atmospheric pressure Tube into the suction chamber, will fill the gap between the teeth, and with the gear rotation, the oil to the left side of the pressure chamber. On the side of the press area, as the teeth gradually enter into engagement here, the volume of the working chamber is continuously reduced and the oil is squeezed out and delivered from the pressure chamber to the pressure line. In the process of gear pump work, as long as the two gears in the same direction of rotation, its absorption, the location of the drain chamber is also unchanged. Here the meshing point of the tooth surface contact line has been divided high, low pressure two chamber plays a role in the oil, so gear pumps do not need to set a special flow control mechanism, which is it and other types of positive displacement hydraulic pump difference.