The invention relates to a backflow device of a supporting and rotating part for a bicycle garage. The backflow device of the supporting and rotating part for the bicycle garage comprises a backflow inclined table and a lifting plate. The relatively-high end of the backflow inclined table is positioned directly below a descending and garage-exiting device of the bicycle garage, the lifting plate is positioned directly below an ascending and garage-entering device of the bicycle garage, after the descending and garage-exiting device delivers a bicycle, the supporting and rotating part for dragging the bicycle enters the relatively-high end of the backflow inclined table and is matched with a slide rail through a large bearing. The supporting and rotating part rolls down to the relatively-lower end of the backflow inclined table along a slide rail by own weight. When a bicycle needs to be stored, the lifting plate slides down. When a U-shaped clamping slot in a U-shaped supporting slot corresponds to the slide rail at the relatively-lower end of the backflow inclined table, a first supporting and rotating part close to the lifting plate rolls down into the U-shaped supporting slot through the large bearing. The supporting and rotating part rises with the lifting plate to the lower portion of a garage lifting and garage-entering device, the supporting and rotating part is waited to be taken by the lifting and parking device into the next use cycle.