Abstract Background The heterogeneity of lung injury in pulmonary acute respiratory distress syndrome (ARDS) may have contributed to the greater response of hyperinflated area with positive end-expiratory pressure (PEEP). PEEP titrated by stress index can reduce the risk of alveolar hyperinflation in patients with pulmonary ARDS. The authors sought to investigate the effects of PEEP titrated by stress index on lung recruitment and protection after recruitment maneuver (RM) in pulmonary ARDS patients. Materials and methods Thirty patients with pulmonary ARDS were enrolled. After RM, PEEP was randomly set according to stress index, oxygenation, static pulmonary compliance (Cst), or lower inflection point (LIP) + 2 cmH2 O strategies. Recruitment volume, gas exchange, respiratory mechanics, and hemodynamic parameters were collected. Results PEEP titrated by stress index (15.1 ± 1.8 cmH2 O) was similar to the levels titrated by oxygenation (14.5 ± 2.9 cmH2 O), higher than that titrated by Cst (11.3 ± 2.5 cmH2 O) and LIP (12.9 ± 1.6 cmH2 O) ( P < 0.05). Compared with baseline, PaO2 /FiO2 and recruitment volume were significantly improved after PEEP titration with the four strategies ( P < 0.05). PaO2 /FiO2 and recruitment volume were similar when using PEEP titrated by stress index and oxygenation but higher than that titrated by Cst and LIP. Compared with baseline, lung compliance increased significantly when PEEP determined by Cst, but there was no difference of Cst in these four strategies. There was no influence of PEEP titration with the four strategies on hemodynamic parameters. Conclusions PEEP titration by stress index might be more beneficial for pulmonary ARDS patients after RM.