Objective To investigate the efficacy of step decompression combined with decompressive craniectomy in treating severe traumatic brain injury (sTBI).Methods A retrospective case series study was conducted to analyze the clinical data of 192 patients with sTBI admitted to Changsha Traditional Chinese Medicine Hospital from January 2016 to April 2018.There were 149 males and 43 females,aged 11-79 years,with an average of 50.1 years.The Glasgow coma score (GCS) was 7-8 points in 57 patients,5-6 points in 45 patients,and 3-4 points in 90 patients.There were 55 patients with unilateral pupil dilation and 88 patients with bilateral pupil dilation.All patients were treated with step decompression and decompressive craniectomy.GCS and pupil sizes before and after operation,intraoperative diffuse brain swelling and acute encephalocele,intraoperative and postoperative delayed bleeding,secondary surgery,mortality during hospitalization,and Glasgow outcome score (GOS) 6 months after injury were recorded.Results At 24 hours after operation,the GCS was 7-8 points in 87 patients,5-6 points in 51 patients,and 3-4 points in 54 patients.The consciousness was significantly improved (P ＜ 0.01),and the pupil was reduced in 56 patients (P ＜ 0.0l).There were four patients with diffuse brain swelling during operation (2.1％),11 patients with acute encephalocele (5.7％),seven patients with delayed bleeding (3.6％),27 patients with postoperative delayed bleeding (14.1％),17 patients receiving secondary surgery (9.7％).Thirty-eight patients died during hospitalization (19.8％).The results of GOS follow-up of 6 months were as follows:there were 50 patients with good recovery (30.0％),36 patients with moderate disability (24.5％),15 patients with severe disability (10.2％),46 patients with persist vegetative states (31.3％),and seven patients died (4.8％).Conclusion For sTBI patients,step decompression combined with decompressive craniectomy can significantly reduce intraoperative diffuse brain swelling and encephalocele,intraoperative,and postoperative delayed bleeding,thus improving the prognosis.