Lumbar puncture is one of the most commonly used tests in neurology. It is mainly used to determine the cerebral pressure and retain the cerebrospinal fluid specimen through puncture. Different tests (such as routine, biochemistry, cytology, antacid staining, viral antibody titer, oligoclonal zone, culture of bacteria, etc.) are sent according to clinical needs. It is mainly used for the diagnosis and auxiliary diagnosis of suspected subarachnoid hemorrhage, intracranial infectious lesions caused by various pathogenic bacteria, autoimmune encephalitis, multiple sclerosis, optic neuromyelitis optica spectrum disorders, Guillain-Barre syndrome, intracranial metastasis, primary CNS lymphoma, meningeal carcinomatosis and other diseases.