Clinically, diuretics generally do not cause sputum clots, but patients with pulmonary heart disease should use diuretics with caution. The main effect of diuretics is to increase urine output and eliminate edema. Side effects are to cause dehydration, decreased blood pressure, electrolyte disorders, blood concentration, increased viscosity, increased thrombosis and myocardial infarction. The use of diuretics in patients with pulmonary heart disease can reduce the patient’s blood volume and achieve the purpose of eliminating edema. When patients with pulmonary heart disease are complicated by heart failure, the use of diuretics can relieve the right ventricular failure caused by water and sodium retention, reduce pulmonary vascular resistance and cardiac load and improve cardiopulmonary function. However, if the diuretic dosage is large, it may lead to rapid diuresis after blood concentration, sputum viscous not easy to cough out and affect the ventilation function. Therefore, when using diuretic therapy in patients with heart failure complicated by pulmonary heart disease, it is necessary to follow the principles of slow, small amount, combined and alternating, and to be cautious of using strong rapid diuretics.