Background Effective oral care can eliminate bacteria from the oral cavity, enhance oral hygiene, and decrease the occurrence of ventilator-associated pneumonia in mechanically ventilated patients with orotracheal intubation. However, proper implementation of oral care for mechanically ventilated adult patients undergoing orotracheal intubation has not been achieved in clinical practice. The aim was to examine the effectiveness of implementing the evidence in oral care for adult mechanically ventilated patients with orotracheal intubation using the framework of evidence-based continued quality improvement and to take actions to improve nursing quality.Methods Pre- and post-implementation studies were carried out employing a framework of evidence-based continuous quality improvement at the comprehensive intensive care unit of Henan Provincial People’s Hospital in Zhengzhou, China from January to December 2022. A baseline survey was conducted to analyse barriers and facilitators to evidence implementation, informing the development of support strategies such as training nursing staff and creating resources, system flow improvements, and tools. After the evidence implementation, changes in nurses, patients, and the system were assessed. The statistical analysis of the data was performed using SPSS 26.0.Results Nurses' knowledge scores and compliance with evidence significantly improved. The modified Beck Oral Assessment Score decreased from (16.28 ± 1.02) to (8.52 ± 0.45). The detection rate of oral sputum pathogens decreased from 50.0–24.0%. Standardized oral care and workflows for mechanically ventilated adult patients undergoing orotracheal intubation were successfully established.Conclusion The framework of evidence-based continuous quality improvement facilitated the successful implementation of evidence in oral care for adult mechanically ventilated patients with orotracheal intubation. This resulted in improved knowledge among nurses and enhanced oral hygiene for patients, ultimately contributing to the ongoing improvement of nursing quality.