Objective To analyze the therapeutic effect of different methods on subdural effusion after decompressive craniectomy (DC) in patients with severe traumatic brain injury (sTBI).Methods Fiftysix patients (38 males and 18 females) who developed subdural effusion following DC from January 2013 to January 2015 were reviewed retrospectively.Age was (36.1 ± 13.5) years (range,12-76 years).Brain injury was from traffic accident in 42 patients,high fall in 7,trauma in 4 and hit by heavy objects in 3.There were 8 patients with accelerated injury,45 decelerated injury and 3 crush injury.Preoperative Glasgow Coma Scale (GCS) score was ≤8 points.Forty-nine patients underwent unilateral DC and 7 bilateral DC.Subdural effusion was found at surgery side in 39 patients,the contralateral side in 10 and both sides in 7.Based on the amount of effusion,the patients were respectively treated with pressure dressing,puncture drainage,cranioplasty or subduro-peritoneal shunt.Effusion ≤ 15 ml was considered to be the criterion of cure.Results Twelve patients with subdural effusion ≤ 30 ml were treated conservatively,and only two developed increased subdural effusion that required surgical intervention.Forty-four patients with the original subdural effusion ＞ 30 ml were given repeated drainage and pressure dressing directly.After surgery,five patients relapsed again and were controlled after subduro-peritoneal shunt.All patients received cranioplasty when subdural effusion was cured.Subdural effusion was all ≤ 15 ml after operation.Conclusion Stepped care including non-operation,puncture drainage and pressure dressing,subduro-peritoneal shunt and cranioplasty is effective in controlling the occurrence and progression of subdural effusion.