Lung cancer is a serious life-threatening malignant tumor and one of the most common malignant tumors in China. In recent years, there is a significant rising trend. In elderly patients with chronic bronchitis, the incidence of lung cancer is higher than that of the general population, but its early symptoms are often easily confused with pre-existing chronic diseases, thus delaying the diagnosis in many cases. Therefore, anyone who has no previous chronic respiratory disease, especially those over 40 years old, should be alerted to the possibility of lung cancer and should undergo further examination if the cough persists for more than three weeks after active treatment. Cough, hemoptysis, chest pain and discomfort are its common symptoms, but they are often ignored by patients. Cough, the earliest and most common symptom of lung cancer patients, is not easy to attract attention because it often resembles cold or bronchitis when it starts. Hemoptysis is the second common symptom of lung cancer, which is often caused by the invasion of cancer tissue into the bronchial mucosa, often as blood sputum, and can last for weeks or months or have intermittent episodes. Due to the small amount or intermittent occurrence of hemoptysis, it is easy to be neglected. In fact, about half of those who present with bloody sputum in middle age or older are due to lung cancer. Therefore, it is important not to be paralyzed when unexplained sputum and blood appear. Chest pain accounts for more than half of lung cancer patients, especially in peripheral lung cancer, chest pain can be the first symptom. Therefore, if there is chest pain in a fixed area for unknown reasons, corresponding examination should be conducted as early as possible. In conclusion, cough, hemoptysis and persistent chest pain are important signs of lung cancer, especially for those who are over 40 years old and have a long and heavy smoking history, they should think about the possibility of lung cancer and should go to thoracic surgery for examination as soon as possible. In conclusion, once abnormal lung manifestations are detected, as long as the diagnosis of lung cancer cannot be completely ruled out, a very positive attitude should be taken to clarify the diagnosis as early as possible and the diagnostic treatment should not be too long. As long as it can be detected early and a comprehensive treatment mainly based on surgery is taken as early as possible, most patients can be cured.