Objective To investigate the impact of a personalized positive end-expiratory pressure （PEEP） strategy， guided by bedside chest CT morphological features， on the outcomes and prognosis of patients with moderate to severe acute respiratory distress syndrome （ARDS）. Methods A prospective clinical controlled study was conducted， involving 92 patients with moderate to severe ARDS admitted to the intensive care unit of Changsha First Hospital between January 2023 and January 2025. Patients were randomly assigned to one of two groups using stratified randomization. The control group （n = 49） received ventilation according to the ARDSnet low PEEP strategy， while the experimental group （n = 43） was managed with a personalized PEEP strategy based on CT morphological characteristics-low PEEP for focal ARDS and high PEEP for diffuse ARDS. The primary outcome measure was 28-day all-cause mortality， while secondary outcomes included duration of mechanical ventilation， length of ICU stay， and indices of respiratory mechanics. Results There was no statistically significant difference in the 28-day mortality rate between the two groups （P > 0.05）. Compared with the control group， the experimental group showed significant improvements in lung compliance and oxygenation index （PaO₂/FiO?） in patients with moderate to severe ARDS， along with significant reductions in plateau pressure， inhaled oxygen concentration （FiO?）， and PEEP levels （all P < 0.05）. Additionally， the duration of mechanical ventilation was significantly shorter in the experimental group （P < 0.05）. However， there was no statistically significant difference in the length of ICU stay between the two groups （P > 0.05）. Conclusion A PEEP strategy guided by chest CT morphology does not significantly reduce mortality in patients with moderate to severe ARDS； however， it effectively improves respiratory mechanics and oxygenation， shortens mechanical ventilation duration， and provides valuable insights for ventilation management in these patients.