The invention discloses a press-machine hydraulic pump. The press-machine hydraulic pump comprises a cover plate, a hydraulic cylinder and a base, and a pump boy and an air pump are arranged below the base. The press-machine hydraulic pump is characterized in that the cover plate is embedded and welded at the edge of an opening in the top of the hydraulic cylinder, an air discharging device is installed on the cover plate, the base is provided with an oil returning valve and an oil discharging hole, and a limiting device is arranged on the side, close to the oil returning valve, on the base; a pair of oil holes are formed in the face, connected with the hydraulic cylinder, of the base, one oil hole of the pair of oil holes is communicated with the pump body, the other oil hole is communicated with the air pump, and a filtering net is riveted and embedded on the oil holes. The structure is stable, the using quantity of fastening pieces and the using quantity of sealing pieces are decreased, leakage of hydraulic oil is avoided, and the service life is prolonged; the connecting stability and convenience of disassembling and assembling of the filtering net can be improved; the oil returning rate of hydraulic oil is accurately controlled, and redundant air is released in time; the operating time is shortened to improve the working efficiency. It can be avoided that due to excessive rotation, a screw of the oil returning valve falls off from the base in the rapid adjusting process, and the using safety is guaranteed.