Objective: To investigate the efficacy of hyperbaric oxygen (HBO) combined with escitalopram in patients with depression and its effect on cognitive function. Methods: From 2016 to 2018, seventy patients with depression aged 18-65 years treated in Affiliated Hospital of Hebei University were selected. Seventy patients with depression meeting the diagnostic criteria of ICD-10 were selected and randomly divided into control group and observation group using a random number table, with 35 patients in each group. The control group was treated with escitalopram, while the observation group was additionally treated with HBO on this basis. The patients were assessed using the Hamilton Depression Scale (HAMD) and Montreal Cognitive Assessment Scale (MoCA) before treatment and two, four and six weeks after treatment. Results: Two weeks after treatment, HAMD score showed a statistically significant difference between the two groups (P < 0.05). No statistically significant differences were found in HAMD score between the two groups four and six weeks after treatment (P > 0.05). Four and six weeks after treatment, MoCA score presented statistically significant differences between the two groups (P < 0.05). Conclusion: Escitalopram combined with HBO in the treatment of depression presents rapid efficacy and a certain effect in improving cognitive function.