The definition of pulmonary wedge pressure is one of the methods used clinically to evaluate cardiac function and is an important test in the assessment of cardiac function in patients with heart failure, and is part of the cardiac catheterization. Pulmonary wedge pressure correlates with the patient’s clinical symptoms and allows assessment of the degree of pulmonary stasis and pulmonary edema, with an increase indicating pulmonary stasis. The normal value of pulmonary artery wedge pressure is 6-12 mmHg, if it is measured at 18-20 mmHg, the patient starts to develop pulmonary stasis, at 20-25 mmHg, moderate pulmonary stasis, at 25-30 mmHg, severe pulmonary stasis, and above 40 mmHg, acute pulmonary edema.