Abstract: Purpose: To study CT features of the cavitary pulmonary tuberculosis and assess the value of CT diagnosis. Materials and methods: CT and plain films were performed in 21 cases with cavitary pulmonary tuberculosis confirmed by pathology or clinic. The CT findings were compared with pathologic and plain film findings. Results: (1) Cavity of pulmonary tuberculosis predominantly involved apical and posterior segments of upper lobes. superior segments of lower lobes. (2) The cavity appeared as round or ellipse. The out wall usually was smooth. The calcification on the cavitary wall was often found. (3) Thickening of the involved bronchial wall were showed. (4) Adjacent pleural thickness were demonstrated. (5) Endobrochial spread manifestation and active lung parenchymal TB were showed outside cavity. 48% of cases had typical CT features and could make a correct diagnosis. In 29%. CT appearances were atypical but suggestive of the diagnosis. In 23%. the correct diagnosis was difficulty to be made by CT. Conclusion: CT is an effective method in diagnosis of pulmonary tuberculosis. The diagnostic accuracy can be improved for atypical CT findings in combining with bronchoscopy. and sputum examination.