As an auxiliary ventilation mode, positive end‑expiratory pressure (PEEP) can effectively prevent atelectasis, improve pulmonary oxygenation, optimize respiratory mechanics in one‑lung ventilation, which also plays a role in pulmonary protection. With growing understanding of PEEP, the clinical application of PEEP, from the initial use of fixed PEEP in combination with a small tidal volume to the present lung recruitment maneuver with a set of individualized PEEP to form an open lung approach, is popular. This review summarizes the application of PEEP in one‑lung ventilation in terms of its mechanism, advantages,side effects, current status and existing problems.