This study is a multicentric randomized controlled study.The objective of this study is to compare the prognosis of patients with ARDS between EIT-oriented individualized PEEP and traditional lower PEEP/FiO2 table-oriented PEEP strategy.

Inclusion Criteria:

Intubated, mechanically ventilated patients with diagnosis of ARDS according to ARDS Berlin standard by attending doctor

Exclusion Criteria:

1. Age < 18 years old and > 90 years old;
2. Pregnancy;
3. EIT contradictions (presence of pacemaker or automatic implantable cardioverter defibrillator);
4. Severe intracranial hypertension;
5. Pneumothorax, pneumomediastinum, subcutaneous emphysema or at high-risk for pneumothorax (e.g., pneumatocele, interstitial lung disease);
6. Unstable hemodynamic status intorerable to lung recruitment and PEEP titration, judged by an attending intensivist; (This may be a transient criterion, since patients meeting this criterion might be included later if hemodynamics improves)
7. End status of disease;
8. Patients or their families refused to participate in the study