Objective To explore the effects of early hyperbaric oxygenation (HBO) on postoperative recovery of intracranial aneurysms patients.Methods The chnical data of 120 postoperative intracranial aneurysms patients were divided into HBO group and control group.The determination of average blood stream speed of middle cerebral artery(MCA) of operation side were recorded at the 1st,3th,7th,14th and 21st day after operation.The operative regional abnormity density volume of CT re - examination were calculated at the 1st,7th,14th and 21st day.The number of cases associated with “symptomatic cerebral vasospasm” was counted at the 3st,7th and 14st day.The functional state ( KPS score) was evaluated at the 3th and 21st day.Result There was no significant difference of MCA average blood stream speed,number of cases associated with “symptomatic cerebral vasospasm” and KPS score between two groups at 3rd day after operation( P ＞ 0.05 ).The MCA average blood stream speed of HBO group was lower than that of control group at the 7th and 14th day after operation ( P ＜ 0.05 and P ＜ 0.01 ).The abnormity density volume of HBO group was less than that of control group at the 14th and 21st day after operation ( P ＜ 0.05 ).The number of cases associated with “symptomatic cerebral vasospasm” of HBO group was smaller than that of control group at the 7th and 14th day after operation ( P ＜0.05).The KPS score of HBO group was higher than that of control group at the 21 st day after operation ( P ＜ 0.05 ).Conclusion The effects of early hyperbaric oxygenation therapy on postoperative intracranial aneurysms patients are good.One of the possible mechanism is release of cerebral vasospasm.