Lung nodules and blood in sputum may be caused by lung cancer, tuberculosis and other diseases. At the same time, it is not excluded that lung nodules are not related to blood in sputum and blood in sputum is caused by other diseases. 1. Lung cancer: if the lung nodules are malignant, when the malignant tumor cells invade the small blood vessels in the lungs, the phenomenon of blood in sputum in the morning may occur. 2. Tuberculosis: Tuberculosis can cause multiple nodular shadows in the lungs. When tuberculosis bacilli invade the small blood vessels in the lungs, blood in sputum may appear, which is a more common symptom of tuberculosis. 3. Other diseases: blood in sputum may be caused by other diseases such as bronchiectasis, bronchopneumonia, etc., not necessarily related to lung nodules. It is recommended that patients with lung nodules should go to regular hospitals in time when they have symptoms of blood in sputum in the morning, so as to clarify the cause of the disease and carry out standardized treatment under the guidance of doctors, so as to avoid delaying the condition.