Objective To evaluate and summarize the best evidence on prevention of Oral Mucosal Pressure Injury (OMPI) in ICU patients with oral endotracheal intubation, and to provide evidence for clinical nursing practice. Methods According to the "6S" evidence model, literature on prevention of OMPI in ICU patients with oral endotracheal intubation was systematically searched from domestic and foreign evidence-based resource databases, comprehensive databases and related association websites. The quality of the literature was evaluated by two researchers after evidence-based training, and the evidence was extracted and summarized in combination with clinical context. Results A total of 14 literatures were included, comprising 1 clinical decision, 1 recommended practice, 3 guidelines, 4 expert consensus reports, 2 systematic reviews, 1 group standard, and 2 evidence summaries. Finally, 25 pieces of best evidence were summarized and categorized into five aspects: assessment, equipment selection, preventive measures, multidisciplinary teams, training and education. Conclusion The best evidence on prevention of OMPI in ICU patients with oral endotracheal intubation can provide evidence-based evidence for clinical nursing practice, and it is recommended that medical staff should adopt the evidence according to the actual clinical context to reduce the incidence of OMPI in this population.