Therefore, this study retrospectively analyzed the clinical characteristics of 397 patients with hydrocephalus and attempted to summarize the relationship between abnormal preoperative CSF leukocyte, chloride, glucose, aspartate aminotransferase, lactate dehydrogenase, adenosine deaminase, lactic acid and protein levels and postoperative infection after a ventriculoperitoneal shunt to guide appropriate operation time for hydrocephalus patients with abnormal CSF. The gene discussed is ADA; the disease is infection.