Objectives:To analyze the safety and clinical effect of airway diagnosis in multifactor suspicious difficult airway patients with complex mouth restriction after entering the operating room.Methods:From March 2018 to May 2023, a total of 21 patients with suspicious difficult airway with complex mouth restriction were collected from the Northwest Women′s and Children′s Hospital and the Third Affiliated Hospital of Air Force Military Medical University, who were evaluated according to LEMON airway evaluation rule. Ventilation capacity score, airway airway score with soft vision mirror and comprehensive airway score of difficult airway were performed after admission to the operating room. Patients diagnosed with non-difficult airway were divided into group N and patients diagnosed with difficult airway were divided into group D. The number and proportion of patients in the two groups were counted, and the process of airway diagnosis, the way of airway establishment, the results, the frequency of hypoventilation during airway establishment, the number of intubation, and the time of airway establishment were analyzed.Results:A total of 15 patients in group N, accounting for 71.4%, underwent rapid intravenous induction nasal intubation after diagnosis of non-difficult airway, and the intubation was successful all the time. No hypoventilation occurred in all patients during intubation. A total of 6 patients in the group D, accounting for 28.6%, were assisted by pure oxygen mask ventilation after diagnosis of difficult airway, and underwent awake nasotracheal intubation after recovery. 4 patients were successfully intubated once, 2 patients were successfully intubated twice, and 1 patient experienced one hypopnea during the evaluation of ventilation capacity. The airway establishment time of the group N was (9.3±0.8)min, and that of the group D was (20.0±2.0)min, the difference was statistically significant ( P<0.05). The airway establishment time of all patients was (12.0±5.0)min, and the awake intubation time was (12.0±0.7.0)min. The proportion of patients satisfied with anesthesia in the group N was higher than that in the group D, and the difference was statistically significant ( P<0.05). No agitation during sevoflurane induction or recovery was observed in both groups. Conclusions:The diagnosis procedure of difficult airway can be safely applied to patients with multi-factor suspicious difficult airway with complex mouth restriction. Most of these patients do not have truly difficult airways; The application of difficult airway diagnosis procedures in these patients can significantly reduce unnecessary awake endotracheal intubation; Compared with the direct choice of awake intubation, following the difficult airway diagnosis procedure does not increase airway establishment time in such patients.