The clinical diagnosis of non-tuberculous mycobacterial lung disease is mainly based on the following points: 1, clinical manifestations, such as cough, coughing sputum, coughing blood, low fever, wasting and weakness, etc., or no obvious symptoms, but only cough, coughing sputum, high fever, chills, chest pain, similar to acute lung infection; 2, imaging changes of the lung, such as lesions found by CT examination; 3, pathogenic examination, after excluding other diseases and ensuring that the specimen is free of Under the premise of exogenous contamination, if one of the following conditions is met, and combined with radiological imaging and clinical diagnosis of NTM lung disease: first, sputum NTM culture for three times with the same pathogenic bacteria; second, sputum NTM culture for two times with the same pathogenic bacteria, one positive antacid bacillus smear; third, bronchoalveolar lavage fluid NTM culture once positive; fourth, alveolar lavage fluid smear positive degree of two + or more ; fifth, positive NTM culture of bronchopulmonary tissue biopsies; sixth, positive NTM culture of granulomas, sputum or bronchoalveolar lavage fluid similar to NTM changes seen on lung biopsy. Extra-pulmonary NTM disease with local and systemic symptoms, with extra-pulmonary tissue and organ lesions found on relevant examinations, and other diseases have been excluded. Positive NTM culture of the tissue at the lesion site can be used as a diagnosis of extra-pulmonary NTM disease under the premise of ensuring that the specimen is free from exogenous contamination.