The invention discloses a supporting device of a building structure. The supporting device includes a bottom plate, fixing bolts, a fixing sleeve, a threaded hole, a connecting plate, a supporting plate, an arc-shaped steel plate, connecting nuts, a fixing block, a biaxial motor, a threaded rod, lead screws, a sliding groove, a movable plate, an anti-skid pad, a rotating shaft, a top plate, connecting rods, lead screw nuts, and a push rod. The supporting device is reasonable in structure, novel in design, easy to operate, and convenient to install, by pushing the push rod, the push rod drives the fixing sleeve and the threaded rod to rotate in the threaded hole in the center of the bottom plate, thus the length of threaded rod at both ends of the bottom plate is adjusted, the two lead screws rotate through the biaxial motor, the lead screw nuts on the two lead screws drive the connecting rods to rotate through the rotating shaft, the two connecting rods drive the movable plate and the anti-skid pad to slide in the sliding groove, the movable plate and the anti-skid pad are tightly attached to the surface of the building structure under the action of the connecting rods, supporting of building structures with different heights and shapes is convenient, and convenience and rapidity are realized.