Objective To assess the value of fluorine-18 fluorodeoxyglucose （18 F-FDG） positron emission tomography （PET） in patients with pulmonary tuberculosis. Methods Fifty-three patients with pulmonary tuberculosis were imaged with 18SF-FDG-PET. 18F-FDG-PET data were analyzed retrospectively with visual method and semiquantitative method. When pulmonary tuberculosis with abnormal 18F-FDG uptake appeared in PET scans confirmed by visual method, their maximum standard uptake value （SUVmax）, mean standard uptake value （SUVmean） and standard uptake value of normal lung （SUVlung） were measured using semiquantitative method. Results Thirty-six pulmonary tuberculous nodules could be detected by 18SF- FDG-PET, and were diagnosed active tuberculosis with visual method. SUVmax（2. 77±1. 20） and SUV mean（2.15±0.86） were higher than SUVlung（0.41± 0.09, Z=-5. 232, P〈0.01 ; Z=- 5. 232, P〈0.01）. Correlations were not found between SUVmax ,SUVmax and nodule size （Dmax, Dmin）, SUVlung, age, blood glucose level in these 36 patients （P〉0.05）. Seventeen fibrosis and calcification cases without caseous necrosis were not found abnormal in 18F-FDG-PET. Conclusion 18F- FDG- PET is useful in diagnosing active tuberculosis , extent of tuberculosis and guiding therapeutic regimen.