Double-stroke and double-thrust hydraulic jack

The invention discloses a double-stroke and double-thrust hydraulic jack. The interior of a cylinder is provided with a through cavity; a cylinder cover and a first guide sleeve are respectively arranged at two ends of the cylinder; a first joint base and a second joint base are arranged on the side wall of the cylinder and are communicated with the through cavity; a first piston is positioned between the first joint base and the second joint base in the cylinder; one end, away from the first piston, of a first piston rod extends out of the through cavity from an opening in the middle part of the first guide sleeve; the interior of the first piston rod is provided with an axial cavity which extends from one end away from the cylinder cover to the middle part; a second piston and a piston rod are arranged in the axial cavity, and sealing pieces are respectively arranged between the piston and the cylinder as well as between the guide sleeve and the piston rod. The double-stroke and double-thrust hydraulic jack has the advantages that for a hydraulic bracket top beam balance maintaining device, the integral structure is compact, and the design is reasonable; the different working pistons can be selected according to the working requirements, so different working pressures and working strokes are realized.