High-density lipoprotein （HDL） is a complex component containing more than 1000 lipids and many lipoproteins. Therefore, its function is very complicated and is easy to change. Normal HDL can protect cardiovascular function, inhibit atherosclerosis. However, in recent years, it is found that HDL can convert to proinflammatory（Oxidized） HDL and lose the role of protecting cardiovascular function, even impair cardiovascular function in some diseases. Thus, HDL may be a risk factor and a therapeutic target for cardiovascular diseases.