One hundred and fifty five cases which pathological diagnosis were chronic lymphadenitis were studied in order to detect infection of acid-fast bacterial L-forms by Ziehl-Neelsen (ZN), intensified kinyoun (IK) and immunohistochemical staining (PAP). The results showed that the expression of M-tuberculosis antibody was positive in 106 cases (68.4%). Among them, 94 cases (60.6%) were positive in IK staining. The positive rate of acid-fast bacillus was 0.6% (1 case), of L-forms was 60% (93 cases). L-forms are higher pleomorphic, spherical bodies, giant bodies or long filaments were shown. The L-forms mostly localised within macrophages, only a few distributed sporadically. The possible causes of misdiagnosis physician and pathologist were discussed. The prognostic value was also suggested.