In the eyes of the general public, lung diseases can be diagnosed with an x-ray or a CT scan, but it is not known that the basis of imaging (CT and x-ray) is pathological changes, and different pathological changes can sometimes appear as similar imaging manifestations. The development of modern medicine advocates evidence-based medicine, i.e., the golden indicator for the diagnosis of disease is established because of the cytology and histology of diagnosis. To achieve this requirement, we use different means to obtain tissue and cellular specimens for different parts of the lung. For lesions in the trachea or around the pulmonary hilum, we reach the lungs through fiberoptic bronchoscopy, under local anesthesia, from the nose and mouth, with little pain and a high safety factor, and the whole procedure is mostly completed within ten minutes. At the end of the procedure, the patient is ready to walk. Through fiberoptic bronchoscopy, we can achieve the value of diagnosis and “lung washing” in two aspects. Of course, there is a shortage of feet and a longevity of inches, and for peripheral lesions outside the lung, the fibrinoscope often cannot be able to peer in, obtain tissue, and complete the diagnosis. For this reason, we can obtain diagnostic specimens through CT-guided percutaneous lung puncture, which is also performed under local anesthesia and is safe and less painful, and the patient can walk after the procedure. For patients with pleural lesions, in the past, all of them were examined by simple pleural fluid extraction, which can diagnose the disease, but for many patients with difficult pleural fluid, it is not enough, so we use pleural biopsy for these patients to achieve histological diagnosis. Through the above mentioned techniques, we have fundamentally solved the problem of the “golden indicator” for the diagnosis of lung diseases, which has enabled a number of difficult patients to obtain a clear diagnosis. We have made everyone have a sense of what is the ultimate diagnostic point of pulmonary diseases, i.e. “golden indicator”.