**Abstract**

This chapter mainly introduces the physicochemical properties, physiological function, and metabolic pathway of low-density lipoprotein (LDL), with emphasis on the mechanism of atherosclerosis caused by LDL and the existing treatment methods. The content of this paper is detailed and comprehensive, including the latest research results in recent years. Different from the published articles, this paper adopts an innovative "tree" structure, with the disease development process as the main line and the molecular mechanism as the branch, showing the clinical significance of the molecular mechanism. The main purpose of the author of this paper is to take LDL as an example, establish a multidimensional knowledge system, and strive to make the complex molecular mechanism vivid.

**Keywords:** low-density lipoprotein, metabolism, atherosclerosis, familial hypercholesterolemia, treatment
