Early stage of lung cancer usually has no symptoms, with the progress of the disease, cough, dyspnea, chest pain, hemoptysis, emaciation and so on may appear. 1. Cough: generally no sputum or little sputum or paroxysmal irritating dry cough with metallic sound; patients with mucinous adenocarcinoma will be accompanied by a large amount of mucous sputum. 2. Difficulty in breathing: the growth of tumor leads to narrowing of airways, which will cause difficulty in breathing, wheezing, and occasionally, wheezing. 3. Chest pain: when the lung disease involves the pleura, patients will feel vague pain in chest due to breathing. 4. Hemoptysis: Central lung cancer or rupture of blood vessels in the lungs will be accompanied by blood in sputum. 5. Wasting: malignant tumors are common in patients with loss of appetite and weight loss. It is suggested that patients with the above symptoms should be alerted and go to the hospital in time for relevant treatments to make a clear diagnosis.