The possible hazards caused by rupture of lung tumor include: bleeding, causing intrapulmonary dissemination of the tumor, secondary infection, triggering pneumothorax or hemopneumothorax and so on. 1. Bleeding: tumor tissue has rich blood supply, there will be more bleeding when it ruptures, and when the amount of bleeding is large, it can cause bronchial blockage of lung segments or even lobes of lungs, which will cause pulmonary atelectasis and seriously affect the respiratory function of patients. 2. Intrapulmonary dissemination of tumor: after rupture of lung tumor, the tumor tissue can be disseminated through bronchial tubes, forming metastatic foci in other lung lobes or even the opposite side of lungs, accelerating the spread of tumor. 3. Secondary infection: hematoma can be formed locally after rupture and bleeding of lung tumor, which is very easy to secondary infection. 4. Causing pneumothorax or hemopneumothorax: rupture of tumor located in the peripheral zone of lung field can cause rupture of pleural cavity and formation of pneumothorax or hemopneumothorax, which will compress the lungs and affect the patient’s respiratory function. It may also lead to pleural metastasis of the tumor. It is recommended that patients should actively seek medical treatment.