Cerebrospinal fluid is found in the ventricles and subarachnoid space, with more cerebrospinal fluid in the lateral fissure pool, occipital pool, cerebellar medullary pool, and middle pool of the subarachnoid space. Lumbar puncture is a common diagnostic procedure that is invasive and requires the patient to lie on his or her side with his or her hands on his or her knees in a protruding lumbar spine. After local sterilization and infiltration anesthesia, a puncture needle is used to puncture and extract cerebrospinal fluid for the appropriate examination. It is important to note that lumbar puncture should not be performed if the patient has local skin inflammation, soft tissue inflammation, spinal cord compression symptoms, or brain herniation status. Normally, cerebrospinal fluid is a colorless, clear liquid that produces an average of about 524 ml per day and can help remove metabolic products and inflammatory exudates and play a similar role to lymphatic fluid from other parts of the body. Cerebrospinal fluid examination generally observes color, clarity, and coagulability, and measures cell count, protein content, sugar and chloride composition, and performs measurements of bacteria, viruses, and specific proteins, and more and more cerebrospinal fluid markers are now being discovered for disease diagnosis. If abnormalities are found by cerebrospinal fluid examination, one needs to be alert for related central nervous system diseases, such as central nervous system infections, central nervous system desmoplasia, autoimmune encephalitis, tumors, etc.