Supporting device for supporting building

The invention relates to the technical field of building construction, and discloses a building supporting device which comprises a supporting sleeve, the bottom end of the supporting sleeve is slidably connected with a bottom rod, the bottom end of the bottom rod is rotatably connected with a fixed hinge, the top end of the supporting sleeve is slidably connected with a top rod, and the top end of the top rod is rotatably connected with a hinge. A fixing ring is slidably connected to the outer side of the supporting sleeve, a control assembly is arranged in the supporting sleeve, a fixing assembly is arranged in the hinge, after the hinge and the fixing hinge are attached to a wall and the ground, a sliding plate is pulled out, a spring is contracted to drive a baffle and a connecting rod to move, and therefore a rotating rod is pushed to rotate through movement of the connecting rod; the piston rod drives the piston plate to move through the movement of the pull rod, the air pressure in the concave groove a