【Abstract】 Objective: To investigate the risk factors for hypoxemia in pediatric patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) undergoing adenotonsillectomy under general anesthesia in the post-anesthesia care unit (PACU) without supplemental oxygen, and to provide a theoretical basis for the prevention and management of postoperative hypoxemia in OSAHS patients. Methods: A retrospective analysis was conducted on the clinical data of OSAHS pediatric patients admitted to the PACU without supplemental oxygen from February to June 2023. Patients were divided into a hypoxemia group and a non-hypoxemia group based on the occurrence of hypoxemia in the PACU. Binary logistic regression was used to identify risk factors for postoperative hypoxemia in OSAHS patients. Results: A total of 640 OSAHS pediatric cases were collected, with 612 cases meeting the inclusion criteria. Among them, 140 patients (22.9%) experienced hypoxemia. No statistically significant differences were found between the hypoxemia and non-hypoxemia groups in terms of sex, age, height, weight, body mass index (BMI), preoperative white blood cell count, neutrophil percentage, and the use of remifentanil, midazolam, or dexmedetomidine. However, significant differences were observed in lymphocyte percentage, sufentanil consumption, history of cough within one week before surgery, abnormal chest imaging, and positive COVID-19 IgG antibodies (P 0.05). Logistic regression analysis identified abnormal chest imaging with increased and blurred lung markings, a history of cough within one week before surgery, prior COVID-19 infection, and sufentanil dosage as independent risk factors for postoperative hypoxemia in OSAHS patients. Conclusion: The occurrence of postoperative hypoxemia in pediatric OSAHS patients is associated with multiple factors, including preoperative cough, abnormal chest imaging (increased and blurred lung markings), and a recent COVID-19 infection. It is recommended to enhance perioperative respiratory monitoring and management for patients with these risk factors to reduce the risk of postoperative hypoxemia.