Abstract: Apolipoprotein B (apoB), an essential structural component of lipoproteins responsible for lipid transportation, circulates in two forms in human, apoB-100 and apoB-48. The generation of apoB-48 is due to the apoB-100 mRNA editing. ApoB-48-containing lipoproteins cannot be converted into the atherogenic low dendity lipoproteins. ApoB RNA editing involves precise deamination of a single nucleotide by a coordinated protein, which is regulated by many elements. Accurate components in the editosome and their role remain unclear. Understanding of the mechanism responsible for apoB mRNA editing will provide the theoretical basis for lipoprotein-related diseases.