Objective To compare the clinical effect and prognosis of hydrocephalus underwent ventriculoperitoneal(VP)shunt at different time.Methods The clinical data of 130 patients with secondary hydrocephalus admitted to the Department of Neurosurgery,The First Affiliated Hospital of Nanjing Medical University from September 2022 to August 2023 were analyzed retrospectively.The improvement of Glasgow coma scale(GCS),Barthel index(BI),and mini mental state examination(MMSE)before and after surgical treatment at different times were studied.Results The GCS,BI and MMSE of all groups after VP shunt were significantly increased(P<0.05).Among them,there was no significant statistical difference in clinical effect between the 0-3 months group and the 3-6 months group,but it was better than the group above 6 months.Conclusions For the patients with secondary hydrocephalus after craniocerebral injury,cerebral hemorrhage,intracranial tumor and intracranial aneurysm surgery,the treatment of VP shunt can effectively improve the neurological function,daily living ability and intelligent mental state of the patients.The operation time should be within 6 months.