There are two types of hypertension: primary and secondary. Primary hypertension is caused by a variety of reasons, and secondary is caused by other diseases resulting in impaired blood pressure regulation. The main principle of primary hypertension: elevated sympathetic nerve activity, adverse stimulation of the internal environment stimulates the endothelial nerves of the brain, leading to uncontrolled regulation of the subcortical centers, and some vasoconstrictive substances are released abnormally, thus elevating blood pressure. It is the activation of RASS. It is polymorphism of genes, which affects receptors, metabolic enzymes, and targets. Secondary hypertension mainly includes primary aldosteronism, renal artery stenosis, acute and chronic glomerulonephritis, and hyperthyroidism, etc. The principle is that the lesion affects the normal regulation of blood pressure more than the body can compensate for, and thus hypertension occurs.