Lung cancer is a malignant tumor of the respiratory system that affects people’s health and currently occupies the first place in the incidence of malignant tumors. The symptoms of lung cancer in early stage are not obvious. In late stage, lung cancer can spread through lymphatic fluid and blood metastasis, and many clinical symptoms such as cough, chest pain and hemoptysis appear. The symptoms are related to the site of primary tumor. Central type lung cancer manifests as irritating dry cough, breath-holding, recurrent episodes of pneumonia in the same area, hemoptysis or asthma, symptoms of laryngeal regurgitation nerve, phrenic nerve compression or superior vena cava compression syndrome. Peripheral tumors are more commonly associated with chest pain, breath-holding or pleural effusion. Large peripheral lesions, central necrosis, and cavities eventually present with lung abscess-like manifestations. The common distant metastatic sites are: lymph nodes, adrenal glands, liver, bone, lung, brain and chest wall, which produce some corresponding symptoms, indicating that lung cancer has reached advanced stage. Invasion of the ipsilateral recurrent laryngeal nerve causes hoarseness, ipsilateral vocal cord paralysis and fixation in the median position; compression of the superior vena cava causes edema of the head, face and upper extremities, and venous anger; invasion of the pleura. It can invade the pleura and cause a large amount of hemorrhagic fluid in the pleural cavity, aggravating shortness of breath, or directly invade the chest wall, causing severe chest pain. It is difficult to tolerate; muscles and skin show atrophic changes, venous rage and edema of upper limbs; and cervical sympathetic nerve syndrome such as ipsilateral ptosis, pupil narrowing, intraocular sunkenness and facial sweating. Some patients with advanced lung cancer have paraneoplastic syndromes, the most common ones accompanied by such symptoms are small cell lung cancer and squamous carcinoma. Common tumor-associated syndromes include: osteoarthrosis of pulmonary origin syndrome (pestle and mortar fingers, osteoarthrosis, periosteal hyperplasia, etc.), SIADH (syndrome of abnormal secretion of antidiuretic hormone), hypercalcemia, etc., and Cushing’s syndrome, myasthenia gravis or male breast enlargement. Patients have neuromuscular symptoms. Some patients have combined skin diseases such as scleroderma and acanthosis nigricans. In conclusion, early diagnosis and early treatment of lung cancer is the key to control the disease and prolong life.