Lung cancer is usually seen in men over 40 years old with a long history of smoking, usually without fever and without obvious symptoms of tuberculosis poisoning. On imaging, the main differentiation is between tuberculosis bulb and peripheral lung cancer, as there may be satellite foci and calcification around the tuberculosis bulb, while there are often cut marks and burrs on the edge of the lung cancer lesion. There are also great similarities in the imaging between cornual tuberculosis and bronchoalveolar epithelial carcinoma, in that cornual tuberculosis often involves the whole lung and is bilateral. In contrast, cor pulmonary carcinoma often involves one lobe or one whole lung, but rarely involves the whole lung bilaterally. Central lung cancer is also easy to be confused with hilar lymphatic tuberculosis, which mostly occurs in adolescents, and the main symptoms are fever, malaise and other symptoms of tuberculosis toxicity, rarely hemoptysis, and more unilateral than bilateral, and more right than left. In combination with sputum tuberculosis bacilli, exfoliative cell examination, fibrinoscopy and biopsy, the diagnosis can often be made in time. Lung cancer and tuberculosis can co-exist and need to be detected. Bacterial pneumonia can be differentiated by its rapid onset, high fever, chills, chest pain with shortness of breath, lesions on X-ray often confined to one lobe or segment of the lung, total blood leukocyte count and neutrophilia, and effective antibiotic therapy; TB also needs to be differentiated from other pathogenic pneumonia, and the key is positive evidence of pathogenicity. In addition to careful analysis of the medical history, lung abscess cavities are most often seen in the lower lobe of the lung, where the inflammatory infiltrate around the abscess is more severe and there are often fluid planes in the cavity. Tuberculosis cavities, on the other hand, mostly occur in the upper lobe of the lung, where the cavity walls are thinner and there are few fluid planes or only shallow fluid planes in the cavity. In addition, pulmonary abscesses have an acute onset, high fever, large amounts of pus sputum, no tuberculosis bacteria in the sputum, but a variety of other bacteria, increased blood white blood cell count and neutrophils, and effective antibiotic therapy. Chronic fibrous cavity combined with infection is easily confused with chronic lung abscess, which is sputum negative for tuberculosis, and the differentiation is generally not difficult. Benign tumors of the lung, such as malignant tumor, sclerosing hemangioma, lipoma, etc., are generally asymptomatic or mildly symptomatic, with a long course and slow growth, and are mostly detected during health checkups, without satellite lesions. Bronchiectasis with a history of chronic cough, coughing up pus and repeated hemoptysis needs to be distinguished from secondary tuberculosis. Chest radiographs mostly show no abnormal findings or only localized thickened lung texture or curly hair shadows, and CT can help confirm the diagnosis. It should be alerted that purulent bronchiectasis can be complicated by tuberculosis infection and should be noted during bacteriological testing. VI. Nodular disease Nodular disease is a granulomatous disease with multisystemic multi-organ involvement. It often invades the lungs and bilateral hilar lymph nodes, and more than 90% of them have clinical changes in the lungs. It is a self-limiting disease, and most of them have a good prognosis with a tendency of natural remission. In contrast, in hilar lymph node tuberculosis, the patient is younger, mostly under 20 years of age, often with low-grade toxicity symptoms, mostly positive tuberculin tests, and hilar lymph node enlargement is usually unilateral and sometimes calcified. Primary pulmonary lesions may be seen. The nodular disease antigen (Kveim) test may assist in the identification. Non-tuberculous mycobacterial pneumopathy Non-tuberculous mycobacteria (NTM) refers to all mycobacteria other than Mycobacterium tuberculosis and Mycobacterium leprae, which can cause lesions in various tissues and organs. The differential diagnosis is based on strain identification. Eight, other febrile diseases: acute cornual tuberculosis with high fever, hepatosplenomegaly, leukopenia or leukemia-like reactions, and typhoid fever, sepsis, leukemia manifestations have confusion, need to be carefully differentiated according to their respective characteristics.