Objective To investigate the risk factors for postoperative hydrocephalus in patients with severe traumatic brain injury.Methods A retrospective analysis was performed on the clinical data of 276 patients with severe traumatic brain injury treated by surgery. Follow-up was performed for six months. These patients were divided into hydrocephalus group (n=47) and non-hydrocephalus group (n=229) according to the diagnostic criteria for hydrocephalus. The two groups were compared in terms of cerebral contusion and laceration, intraventricular hemorrhage, subdural hematoma, epidural hematoma, skull injury, linear skull fracture, cerebrospinal fluid protein level, cerebrospinal fluid pressure, and so on, and these factors were subjected to univariate analysis and stepwise logistic regression analysis.Results The follow-up results showed that the incidence of postoperative hydrocephalus in patients with severe traumatic brain injury treated by surgery was 17.03%(47/276). The univariate analysis showed that there were significant differences in age, intraventricular hemorrhage, subdural hematoma, coma (presence or absence and duration), Glasgow Coma Scale (GCS) score, decompressive craniectomy, traumatic subarachnoid hemorrhage, Galveston Orientation and Amnesia Test, and Function Independent Measure between the two groups (P<0.05). The logistic regression analysis showed that the factors related to postoperative hydrocephalus in patients with severe traumatic brain injury were age, subdural hematoma, coma (presence or absence and duration), GCS score, and decompressive craniotomy.Conclusions Older age, subdural hematoma, low GCS score, and decompressive craniotomy are risk factors for postoperative hydrocephalus in patients with severe traumatic brain injury.