Early stage lung cancer is insidious and often lacks typical symptoms, or only shows non-specific symptoms such as weakness, loss of appetite or weight loss, so it is not easy to attract attention. With the development of the disease, the following symptoms may appear gradually. Cough: It is the most common symptom of lung cancer. When the tumor accumulates trachea and bronchus, it often manifests as irritating cough, i.e. dry cough or paroxysmal choking cough without or with little sputum, and it is not easily controlled by drugs. Hemoptysis: about half of the patients with squamous lung cancer have this symptom, which manifests as persistent or intermittent repeated small amount of hemoptysis or blood in sputum, coughing up blood indicates that the tumor involves the microvasculature of tracheal mucosa. Coughing up blood indicates that the tumor involves the microvasculature of the tracheal mucosa. When the cancer encroaches on large blood vessels, it may cause massive hemoptysis. Chest tightness or shortness of breath: If the tumor is combined with obstructive pulmonary atelectasis, pneumonia and large amount of pleural fluid, chest tightness, shortness of breath after activity, shortness of breath or even difficulty in lying down can occur. 2.Symptoms caused by local invasion of tumor: Chest pain: When tumor invades pleura or soft tissues of chest wall or ribs, it can cause chest pain, which is manifested as stabbing pain or swelling pain in fixed area and often aggravated when coughing or deep breathing. Difficulty in swallowing: Cancer invading or compressing the esophagus can cause difficulty in swallowing, or even erosion penetrating the wall of the tube and forming broncho-esophageal fistula, leading to choking and coughing when eating and lung infection. Hoarseness: Cancer metastasis causes enlargement of mediastinal lymph nodes and compression of the recurrent laryngeal nerve (more common on the left side), resulting in vocal cord paralysis, which can lead to hoarseness and even choking on drinking water. Superior vena cava syndrome: The tumor compresses the superior vena cava, causing obstruction of blood return to the upper body, resulting in edema of the head, face, neck and upper limbs, and anger of veins in the anterior chest, causing headache, dizziness and severe respiratory difficulties. 3. Symptoms of distant metastasis of cancer: The most likely distant metastasis of lung cancer patients are brain, liver, bone and adrenal gland. In the case of brain metastasis, headache, nausea, vomiting, unfavorable limb movement, etc.; in the case of liver metastasis, anorexia, jaundice, pain in liver area, ascites, etc., and abnormal liver function in hospital; in the case of metastasis to bones, severe local pain and even pathological fracture may occur, and the common sites of bone metastasis are vertebrae, ribs and skull. 4. Accompanying symptoms of lung cancer: A few patients will have a group of extra-pulmonary manifestations due to the effect of ectopic hormones secreted by tumor, which is also called “paraneoplastic syndrome”. Such as osteoarthrosis and pestle finger, acanthosis nigricans, hyponatremia, hyperadrenocorticism, gynecomastia, myasthenia gravis, spinal cerebellar degeneration, peripheral neurodegeneration, etc. The above extra-pulmonary symptoms are most common in China, such as osteoarthrosis and pestle and mortar.