Abstract: This paper studies the e ects of coronary artery stenosis of intermediate severity on atherosclerotic process using fluid-structure interaction method. The aim of the study was to analysis the impact of area stenosis (AS = 50%, 65%, 75%) and lesion length (LL = 10 mm, 15 mm, 20 mm) on hemodynamic parameters. Through numerical simulations, it is found that a big margin of oscillating wall shear stress was generated in the branch of coronary artery stenosis and a low wall shear stress was generated in the downstream of stenosis when area stenosis and lesion length increase. The length of the recirculation zone downstream of the stenosis will present with S-shaped growth and the maximum shear rate will grow as parabolic at the same time. In addition, stenosis can bring about a significant decline in pressure. Hemodynamic parameters results show that, intermediate severity area stenosis and lesion length are the factors may cause thrombosis, clinical should attach importance to it.