microRNA(miRNA) are short,about 22-nucleotides-long non-coding RNA.microRNA typically control the expression of their target genes in post-transcriptional level by imperfect base pairing to the 3′ untranslated regions of mRNA.microRNA are involved in the control of a wide range of biological functions including development,differentiation and apoptosis.Whats more,misexpression of microRNA has been discovered as a pathogenic mechanism in several diseases,such as viral infections,diabetes mellitus,cardiovascular diseases and cancers.As the list of microRNA grows,there is a growing awareness of their importance in the regulation of substance metabolism.In this review,we first outline the biogenesis and mechanism of microRNA,and then discuss their relevance to cholesterol metabolism.