Coughing up blood is not necessarily lung cancer, such as regular pneumonia or irritating cough or cold, when the pressure of coughing increases, the small capillaries of lung will rupture and blood in sputum will appear. A major coughing up of blood is when the large blood vessels in the lung are invaded. When invaded, it is not always lung cancer, for example, tuberculosis and bronchial dilatation will increase the pressure to rupture the capillaries, and part of the inflammation invades the surrounding area with exudation and exudate, and there will also be exudation of blood, which will be coughed up through the lung. Coughing up blood and bronchoscopy suggest lesions in the branches of the bronchus, and routine biopsy will find cancer cells according to pathology before the final diagnosis of lung cancer is 100%. Therefore, coughing, coughing blood and blood in sputum only represent lesions in the lungs. Whether the lesions are benign or malignant requires further diagnosis and the final pathological diagnosis, and then the corresponding treatment. There may also be sudden aggravation during the treatment process, which needs to be carefully analyzed and given the correct diagnosis and treatment.