In despite of an effective treatment for aneurysmal subarachnoid hemorrhage (aSAH), delayed cerebral ischemia (DCI) is also a common complication, and it will have significant impacts on the recovery of neurological functions. In this study, we aim to investigate the efficacy of hyperbaric oxygen therapy (HBOT) in the rehabilitation treatment of aSAH. In this study, a total of 98 patients with aSAH and 25 healthy individuals were recruited. Among the patients, 51 individuals received the application of HBOT after the effective treatment of aSAH, while other 47 individuals just received physical rehabilitation. Modified Rankin scale (mRS) and mini-mental state examination (MMSE) scales at 7 days after aSAH were applied for all patients to determine the baselines of neurological deficits and cognitive functions. Attention network test (ANT) was performed at the 6th month. The results indicated that the patients receiving HBOT had a lower incidence of DCI (p=0.026) and a better improvement of executive control function (p<0.001) of ANT, in comparison with those without HBOT. However, there were no differences of orienting, alerting, mean reaction time and accuracy between the two groups. In summary, early hyperbaric oxygen therapy reduced the DCI rate in aSAH patients and consequently promote the improvement of the executive control function of ANT.