Cerebrospinal fluid examination is of great clinical importance. For cerebrospinal fluid examination, it mainly includes routine cerebrospinal fluid, biochemistry, smear and culture. The routine aspect of the cerebrospinal fluid is very important in assessing whether there is an intracranial infection or the presence of hemorrhage. If the routine cerebrospinal fluid indicates elevated white blood cells, there may be a combined intracranial infection. If the erythrocytes are high, intracranial hemorrhage may be present. In terms of cerebrospinal fluid biochemistry, if sugar and chloride are decreased, this may indicate inflammatory diseases such as tuberculous meningitis and fungal meningitis. Elevated cerebrospinal fluid protein may indicate lesions in the ventricular canal and meninges. The smear and culture of cerebrospinal fluid is very important to determine the presence of intracranial infection and the specific bacteria of the infection.