If the patchy dense shadow occurs in the upper lobe of the lung, it cannot be ruled out that the lung has been infected with tuberculosis. Therefore, a series of tests such as tuberculosis antibody, sputum test for antacid bacilli, fibrinoscopy, T-cell test for tuberculosis infection, and blood sedimentation are needed, including the gold standard test for sputum test for antacid bacilli. If the result is positive, a patchy dense shadow is most often considered as a tuberculosis infection. Patchy dense shadow can also occur in pneumonia, old tuberculosis, bronchiectasis with infection, tumor and a series of other diseases, which require further improvement of blood routine, fibrinoscopy, tumor shedding cells, and even mass aspiration, in order to further clarify whether the lesion is benign or malignant, and give a series of treatment such as surgery or radiotherapy or chemotherapy. Therefore, once the patchy dense shadow is detected, further high-resolution CT of the chest is needed to understand the area, size and nature of the dense shadow, and to give targeted examination and treatment.