The patient has normal lung CT, which indicates that the lungs can exclude occupational disease or tuberculosis, etc., but there is also hemoptysis, which may be caused by bronchial diseases, cardiovascular diseases, blood diseases, etc. 1. Bronchial disease: when the patient suffers from bronchial disease, such as bronchitis, bronchial dilatation, etc., it may cause the rupture of bronchial mucosal capillaries, which may lead to hemoptysis even though no obvious foci are detected by CT of lungs. 2. Cardiovascular diseases: cardiovascular diseases may cause this kind of situation, the common diseases are mitral stenosis, pulmonary hypertension, congenital heart disease, left ventricular failure, etc., a few patients may also be accompanied by blood in the sputum, pink foamy sputum, chest tightness and so on. 3. Blood diseases: when patients suffer from leukemia, thrombocytopenia and other blood diseases, their own coagulation function is poor, mucous membranes, subcutaneous and other structures are prone to hemorrhage, which may lead to patients with normal CT and hemoptysis. Lung CT is normal, but also hemoptysis, may also be seen in other diseases, such as hemorrhagic fever, systemic lupus erythematosus, etc., it is recommended that the patient consult a doctor in a timely manner for examination, to clarify the condition of the targeted treatment, pay attention to rest in life, maintain a good mood, and once the condition worsens, it is necessary to consult a doctor in a timely manner for treatment.