The invention discloses a shared bicycle capable of automatically adjusting height, which includes a frame, a saddle, a handlebar, rings and front wheels; the saddle is arranged above the vehicle frame, the handlebar is welded to one side of the frame, A ferrule is welded at the center position of the front wheel, A rotating cavity is arranged on the ferrule, the ferrule is located in the rotatingcavity, One side of the frame is symmetrically welded with two front forks, the ferrule is positioned between the two front forks, and the two front forks are sleeved on the ferrule, a thin shaft isarranged in the rotating cavity, two thick shafts are symmetrically welded on the thin shaft, the two thick shafts are rotatably connected with the inner wall of the rotating cavity, and a coil is fixedly installed on the thin shaft. The invention realizes the automatic adjustment of the height of the saddle of the shared bicycle, improves the safety of riding at night, improves the use efficiencyof the shared bicycle at night, and has the advantages of safety, environmental protection and strong practicability.