Hypertension is the most certain and important risk factor in cardiovascular diseases. Lack of clinical symptoms in the early stage of hypertension, long-term elevated blood pressure can damage important target organs such as brain, heart, kidney and large blood vessels, leading to stroke, coronary heart disease, myocardial hypertrophy, large blood vessel damage, kidney damage, etc. They are the main reason why some hypertensive patients eventually become disabled and even life-threatening. HCY is a sulfur-containing amino acid in the same family as cysteine, a normal metabolite of the methionine cycle, and an important intermediate in energy metabolism and many methylation-requiring reactions in the body. It is produced in vivo by methionine transmethylation and is not involved in protein synthesis per se. When there is a deficiency of enzymes or cofactors related to its metabolism, it can lead to disorders of homocysteine metabolism. There are three forms of homocysteine in serum: HCY, HCY disulfide, and HCY-cysteine. The free form is rare in normal human body, about 70-80% is bound to clear protein in the form of disulfide, and 20-30% is bound to dimer by itself, and the three are collectively called total HCY. Current research shows that homocysteine (HCY) causes NO metabolism disorder by damaging vascular endothelial cells, leading to increased elasticity and stiffness of large arteries and causing the formation of hypertension. Normal human HCY levels are low, higher in men than in women, and increase with age. The pathogenic mechanism of homocysteine is believed to be the damage to vascular endothelial cells, the promotion of vascular smooth muscle proliferation, and the increase of platelet adhesion in blood. In recent years, the relationship between homocysteine and cardiovascular diseases has received increasing attention. Many studies have shown that supplementation with folic acid, VitB12 VitB6 can reduce plasma HCY levels. Therefore, early clinical detection of HCY and timely detection and treatment of hyperhomocysteinemia are important for early intervention and treatment of hypertension.