Lung nodule malignancy is usually cancer. Primary lung cancer is the most common malignant tumor and can be broadly classified into non-small cell lung cancer and small cell lung cancer in terms of pathology and treatment. Among them, non-small cell lung cancer accounts for about 80%-85%. 1. Causes: The causes of lung cancer are not completely clear so far. The risk factors of lung cancer are mainly smoking and passive smoking, followed by indoor pollution such as indoor fuel and cooking fumes, occupational factors such as asbestos, nickel, arsenic and other related special occupational exposure as well as genetic factors, etc. Long-term and heavy smoking is the most common cause of lung cancer. Long-term heavy smoking is the most important risk factor for lung cancer. The higher the amount of smoking, the earlier the age of initiation, and the longer the number of years of smoking, the higher the risk of lung cancer. 2. Clinical manifestations: local growth of primary tumor cells of lung cancer may cause related symptoms, such as coughing, coughing up sputum, blood in sputum, hemoptysis, dyspnea, fever, emaciation and so on. Tumor invasion of central nerve appears nausea, vomiting, headache and other symptoms. Violation of bone tissue may cause severe pain. 3. Treatment: Early detection of lung cancer can be treated by surgery, supplemented by radiotherapy. Advanced lung cancer can be treated with palliative chemotherapy, targeted therapy and immunotherapy. Malignant tumor of lung nodule is lung cancer, which is staged according to the size of nodule, the presence or absence of lymphatic metastasis and distant metastasis. The earlier the staging, the better the treatment effect is, and the lung nodule should be treated in time when the lung nodule is a malignant tumor, so as to miss the best treatment time.