Closestool and closestool water-saving device

The utility model discloses a closestool water-saving device which comprises a water tank, a piston, a supporting rod, a pressing rod and a piston rod, wherein the bottom of the water tank is provided with a water inlet and a water outlet; the piston is arranged in the water tank and matched with the inside wall of the water tank; the supporting rod extends upwards along the axial direction of the water tank; the pressing rod is arranged at the top end of the supporting rod rotatablely; and two ends of the piston rod are rotatablely connected with the pressing rod and the piston respectively. In the closestool water-saving device, the piston is arranged in the water tank and connected with the piston rod and the pressing rod, and the piston is driven to move downwards by pressing down or lifting up the pressing rod to exert a certain pressure on the water in the water tank, so as to increase the impulse of the water flowing out of the water outlet, so that less water can flush heavier objects. Therefore, wate