Pulmonary hemorrhage is a serious disease and one of the medical emergencies. It occurs due to vascular lesions and ruptures in the lungs, and there are many causes of pulmonary hemorrhage, such as bronchiectasis, tuberculosis, lung tumors, pulmonary vascular malformations, vasculitis, and nephritis syndrome. Pulmonary hemorrhage can be manifested as blood in sputum, small amount of hemoptysis or large hemoptysis, etc. Especially in large hemoptysis, blood clots may block the airway and life-threatening asphyxia may occur, and hemoptysis may also lead to complications such as pulmonary atelectasis, aspiration pneumonia and hemorrhagic shock. When pulmonary hemorrhage occurs, regardless of the size of the hemorrhage, attention should be paid to actively search for the cause and treat the cause symptomatically to avoid serious complications.