The invention discloses a stroke-adjustable automatic repetitive hydraulic cylinder which comprises a hydraulic cylinder body. The hydraulic cylinder body is provided with a power liquid inlet pipeline, and the power liquid inlet pipe communicates with a lower hydraulic cavity through a lower hydraulic cavity pipeline. A piston capable of vertically sliding is arranged on the upper portion of thelower hydraulic cavity, and a piston rod in the center of the piston penetrates through the lower hydraulic cavity. A stroke adjusting plate is fixedly mounted at the lower end of the piston rod, anda valve element core capable of vertically sliding is arranged at the position, on one side of the piston rod, of the hydraulic cylinder body. The upper end of the valve element rod is located in thelower hydraulic cavity, and the valve element rod communicates with a sliding valve bottom chamber through a reversing hydraulic signal pipe. A sliding valve is arranged in the sliding valve bottom chamber, and one side of a sliding valve communicates with an upper hydraulic cavity through an upper hydraulic pipeline. The side, opposite to the upper hydraulic pipeline, of the sliding valve is connected with a low-pressure power liquid pipeline, and the other end of the low-pressure power liquid pipeline communicates with the valve element rod. The stroke-adjustable automatic repetitive hydraulic cylinder has the beneficial effects that the valve can be reasonably switched through power liquid, and therefore the effect of automatically adjusting the stroke is achieved, and the requirementsof special work environments and work tasks can be met.