Aim To investigate the relationship between age a nd the development o f atherosclerosis. Methods The mictroarchitecture of intima at apical and later al zones was studied respectively at branch regions of human abdominal aorta in f erior mesenteric artery using transmission electron microscopy (n=30, age ranges from 1 day to 77 years). Results With aging, the th ickness of intima had no a pparent changes at apical zones, where smooth muscle cells turned into constract ile phenotypies and decreased in number, without atherosclerotic lesions; While the thickness of intima increased significantly, where smooth muscle cells remai ned in synthetic states and slightly increased in number, with some atherosclero tic lesions such as lipid deposition, edema, et al. Conclusions The intima at lateral zones has some distinct structural peculiarities with age, which is morp hological basis of atherosclerosis. That is likely caused by hemodynamic status there.