Cholesterol is existed in the form of lipoproteins in the blood. LDL(Low density lipoprotein) is the main carrier for transporting endogenous cholesterol, and LDL is degraded and transformed by binding to low density lipoprotein receptor (LDL-R) on cell membrane. LDL-C(Low density lipoprotein Cholesterol) concentration was positively correlated with the incidence of coronary heart disease. LDL-C-+ was an important index to evaluate the risk factors of coronary heart disease.