Whether or not a patchy shadow in the lungs is important cannot be generalized, but requires a thorough judgment. The clinical significance of a patchy lung shadow, which is an intrapulmonary lesion detected on chest radiograph or CT examination, should be combined with other clinical manifestations. 1. Infectious diseases: such as bacterial infection, viral infection, mycoplasma, chlamydia, legionella and other pathogenic microbial infections can lead to pulmonary patchy shadow, and it is the most common cause. Patients may combine with cough, sputum, fever and other manifestations, if the symptoms are mild, generally does not matter, timely anti-infective treatment, lung patchy shadow can disappear. 2. Tuberculosis: Mycobacterium tuberculosis infection, the lungs can have patchy shadow. Patients may combine with low afternoon fever, night sweats, cough, hemoptysis and other manifestations. If tuberculosis is suspected, patients should consult a specialist as soon as possible to avoid delaying the condition. Anti-tuberculosis drugs such as rifampicin and isoniazid can be used for treatment, and the patchy shadow in the lungs may become smaller or disappear. 3. Lung cancer: tumor lesions can sometimes be seen as patchy shadow changes. Patients may have cough, hemoptysis or even dyspnea. It is necessary to consult the doctor in time for further examination to confirm the diagnosis, and decide on surgical resection, chemotherapy, radiotherapy or targeted therapy according to the specific conditions of the disease. In short, it is necessary to go to a regular hospital in time to see a doctor to clarify the cause of the disease, and then give targeted treatment, otherwise there may be a delay in diagnosis and treatment, affecting the clinical prognosis.