Hypertension is categorized into primary hypertension and secondary hypertension according to whether the cause is clear or not. The etiology of primary hypertension is still unclear, while the etiology of secondary hypertension mainly includes renal disease, endocrine disease, cardiovascular disease, and other diseases. 1. The cause of primary hypertension is still unclear. However, it is related to heredity, high salt and high fat, overweight, long-term mental stress and other triggering factors. 2. Secondary hypertension (1) Kidney disease. The main causes of hypertension are glomerulonephritis, polycystic kidney chronic pyelonephritis, diabetic nephropathy, renal artery stenosis and so on. (2) Endocrine diseases. Mainly includes primary aldosteronism, cortisolism, pheochromocytoma, etc. (3) Cardiovascular diseases. Mainly includes aortic insufficiency, aortic constriction, large multiple aortitis, complete atrioventricular block and so on. (4) Other diseases. For example, craniocerebral trauma, craniocerebral tumor, erythrocytosis, hypertensive syndrome in pregnancy, sleep apnea syndrome and so on. The specific cause of high blood pressure should be confirmed by examination and doctor’s diagnosis in regular hospitals. When abnormal blood pressure occurs, you should seek medical attention to clarify the cause.