The diagnosis of encephalitis can be confirmed based on typical clinical symptoms, neurological examination and specific cerebrospinal fluid biochemical examination. The symptoms are as follows: 1) symptoms: related to the site and severity of viral attack on brain tissue, with a variety of clinical manifestations, typical symptoms are fever, headache, vomiting, convulsions, etc.; 2) neurological physical examination: positive meningeal irritation signs, such as positive Bruch’s sign; 3) cerebrospinal fluid aspiration examination: can be clearly diagnosed, different types of encephalitis, the examination results vary, such as viral encephalitis, cerebrospinal fluid appearance clear, cell The number of cells is not high, mainly lymphocytes; in septic encephalitis, the cerebrospinal fluid is cloudy and contains septic bacteria.