Those who are over the age of forty-five, frequent smokers or those who live in an air-polluted environment for a long period of time should be alerted to the possibility of lung cancer if they develop the following symptoms 1.Patients with chronic respiratory diseases who have increased cough or frequent hemoptysis with no other explanation. 2.Patients who were in good health but have newly developed cough, bloody sputum or hemoptysis, and have not improved after active treatment for more than two weeks after other throat and chest disorders have been excluded. 3.Chest pain, especially chest pain that is not easily relieved after treatment. 4.Lung abscess without foreign body inhalation or other reasons, without manifestation of purulent inflammation, and with poor effect of antibiotic treatment. 5.Recurrent inflammation in the same part of the lung, especially pulmonary segmental inflammation, with slow development and mild symptoms, which disappears after antibiotic treatment or slow absorption or persistent inflammation. 6.Low fever of unknown cause lasting for more than several weeks. This is one of the methods to determine lung cancer. Therefore, people should be alert to the symptoms of lung cancer and go to the hospital regularly for comprehensive physical examination, and once they are sick, they should actively cooperate with doctors for lung cancer treatment so as to reduce the impact of lung cancer. Finally, we should remind people that many lung cancer patients’ symptoms are not very typical, and the usual healthy living habits and regular physical examination are of utmost importance for tumor prevention and early detection!