Objective To study the clinical value of cerebrospinal fluid cytology(csfc)and specific stain in tuberculous meningitis(TBM)-purulent meningitis(PM)and cryptococcal meningitis(CM).Methods The csfc data of 179 patients with TBM,PM and CM were retrospectively analyzed.The samples collected from all of these patients were analyzed by csfc May-Grunwald-Giemsa(MGG)staining,aricine blue staining and Indian ink staining. And the cytospin smears from 70 TBM were simultaneously stained by the immunofluorescence(IF)and immunocytological method to demonstrate the presence of mycobacterial antigen.Results ①TBM group showed a mixed-cell response.At the early stage of disease,the proportion of neutrophilic granulocyte reached 80%,and then reduced gradually.Lyumphoidocyte reaction was the most obvious in 1～2 months.The immunofluorescence(IF)and immunocytological method present a sensitivity of 82.9%and 85.7%,respectively.②Neutrophilic granulocyte was the most cell at acute stage of PM,and it descended quickly once treated with effective antibiotics.③The positive rates to detect CM with csfc MGG,aricine and Indian ink staining were 83.3%,81.8%,and 76.5%,respectively.Conclusion Dynamic observation on cerebrospinal fluid cytology is helpful to boost the differential diagnosis of intracranial infection.