Objective To examine the efficacy of stepwise intracranial decompression in the treatment of acute severe brain injury. Methods A total of 356 patients with acute severe brain injury who underwent standard large decompressive craniectomy from December 2014 to December 2017 were randomly divided into stepwise intracranial decompression group (n=187) and traditional decompression group (n=169). The incidence rate of perioperative complications and Glasgow Outcome Score (GOS) were compared between the two groups. Results The stepwise intracranial decompression group had significantly lower incidence rates of acute encephalocele and delayed hematoma and a significantly higher GOS at 6 months after surgery than the traditional decompression group (all P<0.05). Conclusions Stepwise intracranial decompression reduces the incidence of perioperative complications and improves the prognosis of patients with acute severe brain injury.