The invention discloses a three-parking-space stereo garage structure. The three-parking-space stereo garage structure comprises a vertical supporting base, horizontal lower parking space plates are connected to the left and right sides of the bottom of the front side face of the supporting base respectively, a horizontal upper parking space plate is connected to the portion, above the lower parking space plate on the right side, of the front side face of the supporting base, a groove is formed in the portion, on the left side of the connecting portion of the upper parking space plate, of thefront side face of the supporting base, and a sliding base is slidingly installed in the groove. The three-parking-space stereo garage structure further comprises an inclined transitional plate with the rear side higher than the front side, a connecting plate is integrally connected to the left end of the rear side of the transitional plate, and the rear end of the connecting plate is fixed to thesliding base in the groove. The whole structure is small in occupied area, the fault rate is reduced, and meanwhile the parking efficiency is improved.