Objective To compare the effects of high and low positive end-expiratory pressure (PEEP) levels on prognosis of patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS). Methods The data in PubMed, EMbase, Cochrane Library, CBM and CNKI were retrieved. All randomized controlled trials (RCTs) of treatment of ALI/ARDS with PEEP with high or low level were included. Study selection and assessment, data collection and analyses were undertaken by two independent reviewers. Meta-analyses were done using Cochrane Collaboration's RevMan 5.0 software.Results Six RCTs, involving a total of 2 484 patients of ALI/ARDS were included in the review. According to ventilation strategy, all trials were divided into subgroup A (high PEEP+low tidal volume of 6 ml/kg vs.low PEEP+low tidal volume) and subgroup B (high PEEP+low tidal volume vs. low PEEP+traditional tidal volume). In subgroup B, there were three RCTs, and high PEEP was found to be associated with a lower 28-day mortality [odds ratio (OR)=0. 40, 95% confidence interval (95%CI) 0.22 -0.72, P=0.003]and a lower barotraumas (OR = 0.20,95%CI 0.05 - 0.82, P = 0.02) in patients with ALI/ARDS. In subgroup A, there were three RCTs, and it was found that the differences in 28-day mortality (OR=0.86,95%CI 0.72 - 1.02, P = 0.08) and barotraumas (OR = 1.19, 95%CI 0.89 - 1.58, P= 0.25) were not significant. Conclusion As compared with conventional ventilation, high PEEP and low tidal volume ventilation are associated with improved survival and a lower rate of barotrauma in patients with ALI/ARDS.It is necessary to further confirm the role of high PEEP only in the ventilation strategy in patients with ALI/ARDS.