The invention discloses a gate device applied to self-service equipment and a gate opening and closing method, belonging to gate devices. According to the technical problem to be solved in the invention, the gate device on the self-service equipment is attractive in appearance and compact in structure and has high safety. According to the technical scheme, an outlet of the self-service equipment is formed in a rack; a vertical limiting shaft is fixed on the rack; a gate plate is arranged on the vertical limiting shaft by virtue of a sliding shaft sleeve and a stop clamp spring; a driving motor is fixed on the rack; a gear is arranged on a rotating shaft of the driving motor; a rack is fixed with the gate plate by virtue of a connecting piece; the gate plate is driven to vertically move along the vertical limiting shaft by virtue of meshing motion between the gear and the rack; a positioning piece is arranged on the gate plate and synchronously moves along the gate plate; a sensor A is fixed on the rack above the positioning piece; a sensor B is fixed on the rack below the positioning piece; and the sensor A and the sensor B are connected with the driving motor by virtue of a cable.