The invention discloses a shared bicycle which comprises a frame, a head tube located above the front part of the frame and used for controlling the direction of a front wheel, and a seat mounted at the upper end of the middle part of the frame, wherein a cylinder for adjusting the height of the seat is connected between the seat and the frame; the cylinder is connected with an air pump through a pipeline; the pipeline between the air pump and the cylinder is connected with an electromagnetic valve for controlling the cylinder to be inflated and deflated; the electromagnetic valve is a three-way two-position electromagnetic valve; a fingerprint password input unit for identifying user identity information is mounted at the lower end of the rear part of the seat; the fingerprint password input unit, the air pump and the electromagnetic valve are all electrically connected with a controller. According to the shared bicycle, when the shared bicycle is used for the first time, the seat is adjusted to a riding comfortable height through a seat adjustment button; in the subsequent use process, after the shared bicycle identifies the corresponding user identity information, the height of the seat is automatically adjusted to a height state set at the last time; therefore, a user can feel comfortable when riding the shared bicycle, and the user experience is improved.