Abstract: Atherosclerosis (AS) is the important pathological basis of cardiovascular and cerebrovascular diseases. Proprotein convertase subtilisin/Kexin type9 (PCSK9) is a member of proprotein convertases family that transport the low density lipoprotein receptor (LDL-R) from the surface of liver cells to lysosomes for degradation. It participates in the metabolism of low density lipoprotein cholesterol (LDL-C), which increases the level of LDL-C in the circulation and promotes the development of AS. Recent studies have showed that PCSK9 could promote AS without affecting blood lipid level. That is to say, in addition to its influence on lipid metabolism, PCSK9 could play an independent role in promoting AS. This paper summarized the research progress in the mechanisms of PCSK9 in promoting AS.