Objective Objective To determine the potential factors for development of post-traumatic hydrocephalus (PTH) after decompressive craniectomy (DC).Methods A retrospective study was performed on 62 patients undergone DC after craniocerebral trauma.Based on the incidence of hydrocephalus after DC,the patients were divided into hydrocephalus group (n =15) and non-hydrocephalus group (n =47).The factors including general data information,pre-operative condition,imagine manifestation,operation methods,and surgical parameters were compared between groups to identify the risk factors contributing to the development of PTH.Results No statistical differences were found between the two groups in aspects of gender,age,injury severity score (ISS),pupillary size,pupillary light reflex,Fisher scale of subarachnoid hemorrhage,volume of intracranial occupation,ambient cistern compression,midline shift,intracranial infection,and distance of superior margin of the craniectomy to midline.But there were significant differences of the two groups in whether underwent bilateral craniectomy (x2 =9.235,P ＜0.05),height of craniectomy (t =3.751,P ＜ 0.01),area of craniectomy (t =3.171,P ＜ 0.01) and whether underwent reoperation (x2 =8.335,P ＜ 0.01).Logistic regression analysis indicated that the development of PTH was significantly affected by bilateral craniectomy,large craniectomy and reoperation.Conclusion Bilateral craniectomy,large craniectomy and reoperation are risk factors for the development of PTH after DC.