Meningitis is a common infectious disease of the central nervous system, which is an acute or chronic inflammatory disease caused by the invasion of the meninges by pathogenic microorganisms. Due to the different pathogenic microorganisms, the common types of meningitis are viral meningitis, septic meningitis, tuberculous meningitis and cryptococcal meningitis. Viral meningitis is mostly caused by enterovirus infection and is a benign infectious disease with good prognosis, no sequelae and a short course after symptomatic and supportive treatment. Septic meningitis is an inflammation of the meninges caused by septic bacterial infection, often combined with septic encephalitis or brain abscess, is an extremely serious intracranial infectious disease, the disease is more dangerous, has a high rate of death and disability, its prognosis is closely related to the causative agent, the body condition and whether early and effective antibiotic treatment. Tuberculous meningitis is an inflammatory disease of the meninges caused by Mycobacterium tuberculosis. Its prognosis depends on the severity of the disease, whether the treatment is timely and thorough, and is generally worse in infants and the elderly. Cryptococcal meningitis is a subacute or chronic inflammatory disease caused by a new type of Cryptococcus infection of the meninges, a fungal infection that occurs in people with low or deficient immunity, often with progressive exacerbation, a poor prognosis and a high mortality rate. In conclusion, the prognosis and mortality of meningitis are closely related to the causative microorganism, as well as to the underlying conditions of the patient and the timely and regular use of medication.