Meningitis is a diffuse inflammatory change of the soft meninges and arachnoid membranes caused by various pathogens or other causes, and these causative organisms include viruses, bacteria, fungi, spirochetes, parasites and prions. Because of the uncertainty of the etiology, early clinical manifestations are variable and can lead to death in severe cases or leave serious sequelae, but early aggressive treatment can cure most cases. Meningitis is caused by bloodstream infection, direct infection and retrograde infection, and can be associated with clinical and laboratory changes such as fever, headache, vomiting, positive meningeal irritation, increased cranial pressure, increased white blood cell count, and positive biochemical and other ancillary tests. The main principles of treatment are the selection of sensitive drugs for the causative organisms, symptomatic treatment and prevention of complications. Viral meningitis is an acute meningitis caused by various viral infections, which is a self-limiting disease with a short course and no sequelae and a good prognosis. Septic meningitis is an inflammation of the cerebrospinal membrane caused by septic bacterial infection, often combined with septic encephalitis or brain abscess, and is an extremely serious intracranial infectious disease with a high mortality and disability rate, requiring timely treatment with antibiotics. Tuberculous meningitis is a non-suppurative inflammatory disease of the meninges caused by Mycobacterium tuberculosis, and the prognosis depends on the severity of the disease, the promptness of treatment, and the thoroughness of treatment. In conclusion, meningitis is an infectious disease that requires prompt diagnosis and early treatment to avoid sequelae and other complications.