【Abstract】 Objective To explore the clinical efficacy and safety of hyperbaric oxygen chamber in the treatment of high altitude pulmonary edema. Methods A retrospective cohort study was used to collect 102 patients with acute high altitude pulmonary edema from March 2017 to December 2017 in Ali District People's Hospital of Tibet. They were randomly divided into routine treatment group, hyperbaric oxygen chamber treatment group 1 and hyperbaric oxygen chamber treatment group 2, with 34 cases in each group. The routine treatment group was given routine treatment, while the hyperbaric oxygen cabin treatment group 1 was given hyperbaric oxygen cabin less than 3 times on the basis of routine treatment, and the hyperbaric oxygen cabin treatment group 2 was given hyperbaric oxygen cabin more than 3 times on the basis of routine treatment. The clinical efficacy and safety of the three groups were compared. Results There were significant differences in respiratory rate, heart rate and PaO  2 between the routine treatment group and the hyperbaric oxygen chamber treatment group 1 (P＜0.05), but no significant differences in PaCO  2 (P＞0.05). There were significant differences in respiratory rate, heart rate, PaCO  2 and PaO  2 between routine treatment group and hyperbaric oxygen chamber treatment group (P＜0.05). There were significant differences in heart rate and PaO  2 between group 1 and group 2 (P＜0.05). The total effective rate of hyperbaric oxygen treatment group 2 ＞ hyperbaric oxygen treatment group 1 ＞ conventional treatment group (P ＜ 0.05), the total effective rate of hyperbaric oxygen treatment group 2 ＞ hyperbaric oxygen treatment group 1 ＞ conventional treatment group (P＜0.05). No significant adverse reactions were found in all the three groups. Conclusion Routine treatment combined with hyperbaric oxygen chamber has a significant clinical effect on acute high altitude pulmonary edema. It is a safe and effective treatment method.