Abstract：Objective To elucidate the need of reassessing the diagnosis when residual pulmonary tuberculosis( TB) cavities still exist. Methods FromJan2003 to Jun2007, sixty-seven patients who were initially diagnosed with pulmonary TB and had already completed a short course treatment were enrolled in the current study. All the patients were negative for the sputumTB tests, but still had residual pulmonary cavities. Within three months after the short course treatment, these patients were re-evaluated by bronchoalveolar lavage ( BAL) . Fifty-nine of themwere also re - evaluated by CT-guided percutaneous lung needle biopsy ( PLB) after receiving the informed consent fromthe patients. Results None of the sixty-seven patients was found TB positive by BAL. Among 59 of these patients who had CT-guided PLB, 62 PLB specimens were collected: two specimens were positive for cancer, five for fungi and five for TB, and three for various bacteria. Conclusion Even when the diagnosis of pulmonary TB infection is confirmed and the anti - TB therapy is effective, the diagnosis of other diseases complicated with TB infection should still be considered, especially when there are residual pulmonary TB cavities. To avoid delayed diagnosis of cancer or other infectious disease in pulmonary TB patients, repeated evaluation by using PLB or BAL is encouraged.