Lung cancer is one of the common malignant tumors in China, and early detection and treatment are related to the prognosis of lung cancer. Early diagnosis through suspicious signs is highly necessary and operable. The author has made some summaries on the suspicious signs for early diagnosis of lung cancer in recent years for the benefit of readers. Meaning of early diagnosis. 1.Time: The first stage refers to the time from the appearance of symptoms to the discovery of the mass on X-ray, and the second stage refers to the time from the discovery of the mass on X-ray to the establishment of the diagnosis by special examination; 2.Mode of discovery: positive sputum cytology examination and negative X-ray examination; 3.The diameter of the mass in the lung field is between 0,5 and 1,0 CM, and the diameter of the mass in the lung door is less than 2,0 CM; 4.The diagnosis is established at the appearance of limited emphysema, obstructive pneumonia, obstructive lung Zhang The diagnosis was established at the time of the appearance of limited emphysema, obstructive pneumonia, and obstructive pulmonary stenosis; 5. The diagnosis was established without the presence of proximal (hilar, mediastinal) and distant metastases. The main suspicious signs for early diagnosis are as follows. 1. Patients over forty years of age suddenly present with irritating choking cough or small amount of hemoptysis, chest X-ray showing with or without pulmonary shadow, or sudden appearance of limited emphysema or pulmonary atelectasis without previous history of chronic respiratory disease; 2. It is important to pay high attention. The appearance of a mass shadow in the lung hilum, or a gradually increasing thickening, or a limited widening of the upper mediastinum should be alerted; in addition, the sudden appearance of a large amount of pleural fluid, especially bloody but not obvious symptoms of poisoning; 3. or nodular shadows; progressive increase and thickening of lung shadows at any age; 4. Spherical lung lesions >3-4 cm that cannot be diagnosed as other diseases; isolated, eccentric, or centrifugal cavities in the lungs with thick walls, uneven inner walls, or wall nodules; thick-walled cavities in the lungs but consistently negative sputum for Mycobacterium tuberculosis and ineffective anti-tuberculosis therapy; 5. Progressive dyspnea, foamy sputum more, fever is not obvious, and diffuse corn-like shadow in the lung; 6, apical, hilar or mediastinal mass shadow with corresponding compression, such as hoarseness, Horner’s syndrome, superior vena cava syndrome, etc.; 7, active pulmonary tuberculosis after reasonable anti-tuberculosis treatment, the lesion increases and thickens or the symptoms worsen. There are also sputum-positive patients who have turned negative with anti-tuberculosis treatment, but the symptoms have increased or the shadows have grown. In addition, in patients with chronic tuberculosis, there is a mass or nodular shadow at the lung lesion; 8. In patients with chronic respiratory disease, there is a mass shadow at the lung field or lung hilum, showing eccentric expansion and enlargement; 9. In high-risk groups, there is a mass or nodular shadow over 40 years old.