Objective To evaluate the effect of hyperbaric oxygen therapy (HBOT) in patients with severe traumatic brain injury (STBI) after craniotomy,and evaluate the difference of HBOT effects on the patients whose Glasgow coma score (GCS) were 6-8 scores and 3-5 scores.Methods Using case-control study,61 neurosurgical in-patients with STBl from February 6,2009 to November 25,2010 were divided into two groups by random digits table,30 in HBOT group and 31 in control group.Their GCS at the periods on admission,before HBOT and when they finished HBOT were recorded,as well as the Glasgow outcome score (GOS) before HBOT,finished HBOT,and 3 months after admission (GOS3M).Results The GCS finished HBOT were (12.63 ±2.70) scores in HBOT group and (11.64 ±2.50) scores in GCS 3-5 subgroup,there were statistically differences than those in control group [ (10.61± 3.01 ),(8.44 ± 1.67)scores] (P ＜0.05).The mean rank of GCS finished HBOT improvement (△GOSf) and GOS scores 3months after admission ( △ GOS3M) in HBOT group was 35.37 and 35.87,which were significantly higher than those in control group (26.77 and 26.29) (P ＜0.05).Meanwhile,the mean rank of △GOSf and △ GOS3M in GCS 3-5 subgroup was 12.14 and 13.09,which were significantly higher than those in control group (8.05 and 7.33) (P ＜ 0.05 ).In GCS 6-8 subgroup,there was no significant difference in △ GOSf and △ GOS3M between HBOT group and control group (P ＞ 0.05).Conclusion Early HBOT is effective to improve the recovery of consciousness and prognosis of the postoperative patient with STBI,especially of the patients with the special STBI (GCS 3-5 scores ).