Lung infection is mostly indicated by chest radiographs and chest CT, which indicates that there is a possibility of acute or chronic infection in the patient’s lungs, and the foci of infection are mostly manifested as plaques, exudates, proliferation, nodules or solid lesions. If the patient has cough, sputum, hot flashes, night sweats, blood in the sputum, or even fever, it is necessary to be alert to the possibility of tuberculosis as the focus of infection. If there is a large patchy solid lesion, there is a possibility of lobar pneumonia, and the patient may have symptoms such as coughing, coughing up yellow sputum, chest pain, and high fever. If coughing up pus sputum for a long time, even with blood in sputum, chest X-ray suggests cystic and columnar bronchial dilatation, which indicates that the infection foci are mostly bronchial dilatation with infection. Lung infection foci mostly suggest the possibility of acute and chronic infections, including viral, bacterial, tuberculosis and other unexplained infections, as long as the appearance of patches, exudation and other manifestations on the lungs, mostly suggest the possibility of lung infection foci, and need to further clarify the cause of the infection.