Single-plunger hydraulic pump

The invention discloses a single-column hydraulic pump, which relates to the field of hydraulic reciprocating pumps, and comprises an oil cylinder, a first oil port and a second oil port are respectively arranged at two ends of the oil cylinder; the first piston is movably arranged in the oil cylinder, and the first oil port and the second oil port can achieve reciprocating motion of the first piston through switching of an oil inlet state and an oil outlet state; a first water inlet and outlet assembly and a second water inlet and outlet assembly are arranged at the two ends of the water tank correspondingly; the second piston is arranged in the water cylinder, and the second piston is connected with the first piston through a first piston rod; according to the single-plunger hydraulic pump, a power machine and a crank connecting rod mechanism of a maneuvering reciprocating pump are replaced by the hydraulic pump and the hydraulic cylinder at the power end, the hydraulic pump and the hydraulic cylinder are a