Awareness of the prevention and treatment of hypertension has increased significantly. However, there is another type of “hypertension” that has been neglected, and that is pulmonary hypertension (PH). The normal human body has two sets of blood circulation systems, the body circulation and the pulmonary circulation. Each set of circulation has its own pressure range, and once the pressure of the body circulation is elevated, it forms what we often call “hypertension”. The pressure in the pulmonary circulation can also be elevated, resulting in pulmonary hypertension. Pulmonary hypertension is actually a common clinical condition with complex and diverse causes, which can be caused by a variety of cardiac, pulmonary or pulmonary vascular diseases, eventually leading to right heart failure, which is potentially fatal and has a poor prognosis, but is not easily taken seriously by physicians or patients in the clinical setting. Most patients with pulmonary hypertension have an insidious onset and develop slowly, with no specific symptoms at first, and may only experience some shortness of breath and chest tightness after activity, which may improve after rest, so it is not easy to draw attention to the disease. In the later stage, with further increase of pulmonary artery pressure, shortness of breath, chest pain, dizziness and easy syncope may appear. Severe patients develop symptoms of right heart failure, such as edema of the lower limbs, enlarged liver, and even ascites or pleural fluid. Once the symptoms of right heart failure appear, the prognosis of patients is not optimistic. Therefore, we must be alert to this highly disabling and high mortality disease. According to the latest international classification, pulmonary hypertension can be divided into five major categories: the first is pulmonary hypertension, the second is pulmonary hypertension associated with left heart disease, the third is pulmonary hypertension associated with respiratory disease and/or hypoxia, the fourth is chronic thromboembolic pulmonary hypertension, and the fifth is pulmonary hypertension of unknown or multifactorial origin. It is believed that pulmonary hypertension can be caused by dozens of diseases, including idiopathic pulmonary hypertension, connective tissue diseases such as rheumatoid arthritis and systemic lupus erythematosus, and due to the popularity of weight loss fads, some people who have taken diet pills can also suffer from pulmonary hypertension. Due to environmental pollution and other reasons, pregnant mothers are exposed to various risk factors, leading to a significantly higher incidence of various congenital heart diseases, such as patent ductus arteriosus, atrial septal defect, and ventricular septal defect, which can also develop into pulmonary hypertension if they are not treated promptly and effectively. In the highest cases, the pressure in the pulmonary circulation may even be greater than the pressure in the body circulation (normally, the pressure in the pulmonary circulation is only one-fifth of that in the body circulation), and once this occurs, the opportunity for surgery or intervention is lost. What are the diagnostic criteria for pulmonary hypertension? The most recent criterion is a mean pulmonary artery pressure of ≥25 mmHg measured by right heart catheterization at sea level at rest; in addition, the diagnosis of pulmonary hypertension (the first category of pulmonary hypertension, also known as arterial pulmonary hypertension) should include a pulmonary capillary wedge pressure or left ventricular end-diastolic pressure of ≤15 mmHg in addition to the above criteria. The severity of pulmonary hypertension can be classified as “mild” (25-35 mmHg), “moderate” (36-45 mmHg), and “severe” (≥45 mmHg). What tests should be done to clarify pulmonary hypertension? To clarify the cause of pulmonary hypertension and determine the severity of the disease, relevant tests can be performed: chest X-ray has a high diagnostic value for patients with moderate to severe pulmonary hypertension. Echocardiography is the most important non-invasive test for screening pulmonary hypertension in China, and the recommended standard for the diagnosis of pulmonary hypertension is a systolic pulmonary artery pressure of ≥40 mm Hg. Pulmonary function tests, radionuclide pulmonary ventilation/perfusion scans and high-resolution CT and enhanced CT pulmonary angiography can clarify the presence of pulmonary disease, thromboembolism, and other conditions. Right heart catheterization and acute pulmonary vasodilatation tests are the standard methods to confirm the diagnosis and assess the severity of the disease. How is it treated and prevented? Although the prognosis of pulmonary hypertension is poor, some progress has been made in its treatment. Firstly, in the prevention and treatment, patients need to be given some correct advice about daily life, encouraged to perform appropriate physical exercise physical exercise according to their individual symptoms and provided with rehabilitation guidance, followed by psychological support for such patients, and as patients with pulmonary hypertension are prone to pneumonia, it is important to prevent infection. Treatment is directed at vasoconstriction, endovascular injury, thrombosis and cardiac insufficiency to help restore pulmonary vascular pressure, improve cardiac function and enhance quality of life. Patients with pulmonary hypertension associated with left heart disease, pulmonary hypertension associated with respiratory disease and/or hypoxia can be treated with cardiac and pulmonary disease related therapy. Patients with pulmonary hypertension and chronic thromboembolic pulmonary hypertension can be treated with specific medications, also known as targeted medications, including calcium antagonists, prostacyclin, endothelin receptor antagonists, and 5-type phosphodiesterase inhibitors, the latter three of which are more expensive. Pulmonary artery thromboendarterectomy may also be considered for chronic thromboembolic pulmonary hypertension. In the past, due to the limitations of diagnosis and the lack of safe and effective drug therapy, many patients spent the rest of their lives in pain and despair. Now, with the improvement of the level of diagnostic technology and the release of many new drugs, the treatment of pulmonary hypertension is no longer just a dream.