The carotid sinus of the carotid artery (CA) bifurcation is one of the favored sites for the genesis and development of atherosclerotic lesions. The direct reason is carotid arteries bifurcation and stenoses may lead to great flow pattern change. Aim of this article is to investigate the effect of different eccentric stenosis of internal carotid artery on blood flow. The blood flow in artery is simulated numerically and the simulation is based on convicted reasonable of vascular profile and flow environment in vivo. The simulation or the computer flow dynamic calculation reveals the eccentric stenosis can make great effort to the flow pattern. And more serious stenosis proliferation can be generated. Doppler ultrasound (DUS) are widely used in blood flow detection for the diagnosis of cardiovascular diseases (CAD). It is the gold standard of the diagnosis of vessel related diseases and the color sonography display is familiar for clinicians and internist, we simulated the color sonography of stenosis carotid arteries bifurcation mocked the DUS display method. The results are proved to be visual, detailed and accurate that it can more directly use in clinic. All simulation above can alleviate the effects of measurement errors and can be used as the complement of ordinary ultrasound measures.