Primary tuberculosis often occurs in children with the main types of hilar lymphonode tuberculosis or Ghon complex. When pulmonary tuberculosis aggravates and tubercule bacillus invades pulmonary veins, a disseminated disease may occur clinically. One 8-year-old girl presented with hypodynamia and emaciation. CT indicated the disseminated disease and extensive mediastinal and hilar lymphadenopathy. But she had negative sputum smears and negative PPD test. The bronchi showed inflammatory change in fiberoptic bronchoscopy. Percutaneous transthoracic needle biopsy (PTNB) guided by CT was used as a means for the diagnosis of pulmonary tuberculosis. The case was rapidly diagnosed as sub-acute disseminated pulmonary tuberculosis with the help of combined CT imagine and histology.