The hydraulic pump is the energy conversion device of the hydraulic transmission system. Its function is to transform the mechanical energy of prime mover into pressure energy and transport pressure oil to the system. The selection, installation and commissioning of the hydraulic pump is very important for the whole system to work normally。The structure of hydraulic pump can be divided into four categories: gear pump, vane pump, screw pump and plunger pump. Many factors should be considered when selecting hydraulic pumps.Hydraulic pump is one of the main components to produce and transmit noise. The first is to produce noise, and the second is to transmit noise. Hydraulic pump mainly produces mechanical noise and fluid noise, both of which are directly related to the installation of the pump. Therefore, the hydraulic pump must pay attention to the correct installation.